Energy delivery systems and uses thereof

ABSTRACT

The present invention relates to comprehensive systems, devices and methods for delivering energy to tissue for a wide variety of applications, including medical procedures (e.g., tissue ablation, resection, cautery, vascular thrombosis, treatment of cardiac arrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). In certain embodiments, systems, devices, and methods are provided for delivering energy to difficult to access tissue regions (e.g. peripheral lung tissues), and/or reducing the amount of undesired heat given off during energy delivery.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/867,986, filed on Sep. 28, 2015, which is a continuation ofU.S. patent application Ser. No. 13/696,001, filed on Jan. 17, 2013,which is a national phase application under 35 U.S.C. § 371 of PCTInternational Application No. PCT/US2011/035000, filed on May 3, 2011,which claims priority to U.S. Provisional Patent Application No.61/330,800, filed May 3, 2010, each of which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to comprehensive systems, devices andmethods for delivering energy to tissue for a wide variety ofapplications, including medical procedures (e.g., tissue ablation,resection, cautery, vascular thrombosis, treatment of cardiacarrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). Incertain embodiments, systems, devices, and methods are provided fordelivering energy to difficult to access tissue regions (e.g. peripherallung tissues), and/or reducing the amount of undesired heat given offduring energy delivery.

BACKGROUND

Ablation is an important therapeutic strategy for treating certaintissues such as benign and malignant tumors, cardiac arrhythmias,cardiac dysrhythmias and tachycardia. Most approved ablation systemsutilize radio frequency (RF) energy as the ablating energy source.Accordingly, a variety of RF based catheters and power supplies arecurrently available to physicians. However, RF energy has severallimitations, including the rapid dissipation of energy in surfacetissues resulting in shallow “burns” and failure to access deeper tumoror arrhythmic tissues. Another limitation of RF ablation systems is thetendency of eschar and clot formation to form on the energy emittingelectrodes which limits the further deposition of electrical energy.

Microwave energy is an effective energy source for heating biologicaltissues and is used in such applications as, for example, cancertreatment and preheating of blood prior to infusions. Accordingly, inview of the drawbacks of the traditional ablation techniques, there hasrecently been a great deal of interest in using microwave energy as anablation energy source. The advantage of microwave energy over RF is thedeeper penetration into tissue, insensitivity to charring, lack ofnecessity for grounding, more reliable energy deposition, faster tissueheating, and the capability to produce much larger thermal lesions thanRF, which greatly simplifies the actual ablation procedures.Accordingly, there are a number of devices under development thatutilize electromagnetic energy in the microwave frequency range as theablation energy source (see, e.g., U.S. Pat. Nos. 4,641,649, 5,246,438,5,405,346, 5,314,466, 5,800,494, 5,957,969, 6,471,696, 6,878,147, and6,962,586; each of which is herein incorporated by reference in theirentireties).

Unfortunately, current devices are limited, by size and flexibility, asto the body regions to which they are capable of delivering energy. Forexample, in the lungs, the air paths of the bronchial tree getprogressively narrower as they branch with increasing depth into theperiphery of the lungs. Accurate placement of energy delivery devices tosuch difficult to reach regions is not feasible with current devices.Improved systems and devices for delivering energy to difficult to reachtissue regions are needed.

SUMMARY OF THE INVENTION

The present invention relates to systems, devices and methods fordelivering energy to tissue for a wide variety of applications,including medical procedures (e.g., tissue ablation, resection, cautery,vascular thrombosis, treatment of cardiac arrhythmias and dysrhythmias,electrosurgery, tissue harvest, etc.). In certain embodiments, systems,devices, and methods are provided for treating a tissue region (e.g., atumor) through application of energy. In some embodiments, systems,devices, and methods are provided for accessing difficult to reachtissue regions with energy delivery devices. In some embodiments,systems, devices, and methods are provided for reducing heat releasealong energy transmission lines.

The present invention provides systems, devices, and methods that employcomponents for the delivery of energy to a tissue region (e.g., tumor,lumen, organ, etc.). In some embodiments, the system comprises an energydelivery device and one or more of: a processor, a power supply, a meansof directing, controlling and delivering power (e.g., a power splitter),an imaging system, a tuning system, a temperature adjustment system, anda device placement system.

The present invention is not limited to a particular type of energydelivery device. The present invention contemplates the use of any knownor future developed energy delivery device in the systems of the presentinvention. In some embodiments, existing commercial energy deliverydevices are utilized. In other embodiments, improved energy deliverydevices having an optimized characteristic (e.g., small size, optimizedenergy delivery, optimized impedance, optimized heat dissipation, etc.)are used. In some such embodiments, the energy delivery device isconfigured to deliver energy (e.g., microwave energy) to a tissueregion. In some embodiments, the energy delivery devices are configuredto deliver microwave energy at an optimized characteristic impedance(e.g., configured to operate with a characteristic impedance higher than50Ω) (e.g., between 50 and 90Ω; e.g., higher than 50, . . . , 55, 56,57, 58, 59, 60, 61, 62, . . . 90Ω, preferably at 77Ω) (see, e.g., U.S.patent application Ser. No. 11/728,428; herein incorporated by referencein its entirety).

In some embodiments, the present invention provides devices, systems,and methods for placing energy delivery devices in difficult to reachstructures, tissue regions, and/or organs (e.g. a branched structure(e.g. human lungs). Accordingly, in some embodiments, the presentinvention provides a multiple-catheter system or device comprising: aprimary catheter, which comprises an inner lumen (the primary lumen); achannel catheter, or sheath, which comprises an inner lumen (channellumen), wherein the channel catheter is configured to fit within theprimary lumen; and one or more insertable tools (e.g. steerablenavigation catheter, therapeutic tools (e.g. energy delivery device,biopsy forceps, needles, etc.), etc.), wherein one or more insertabletools are configured to fit within the channel lumen. In someembodiments, the present invention provides a method for accessingdifficult to access tissue regions (e.g. highly branched tissue, e.g.periphery of the lungs) comprising: providing a steerable navigationcatheter within the channel lumen of a channel catheter, wherein thechannel catheter is within the primary lumen of a primary catheter. Insome embodiments, a steerable navigation catheter comprises: i) asteerable tip which allows manipulation of its position within apatient, organ, lumen, and/or tissue by a clinician or operator, and ii)a position sensor, which allows tracking of the steerable navigationcatheter through a patient, organ, lumen, and/or tissue. In someembodiments, a steerable tip of a steerable navigation catheterfunctions by pointing tip of the catheter in the desired direction ofmotion. In some embodiments, manual or automated movement of thecatheter results in movement directed in the direction of the tip. Insome embodiments, a primary catheter, channel catheter, and steerablenavigation catheter are inserted into a tissue region (e.g. bronchi)within a patient, and the primary catheter (e.g. bronchoscope) isinserted as far into the tissue region as the size of the availablespace (e.g. lumen (e.g. lumen of the brochia)) and the size of theprimary catheter (e.g. bronchoscope) will allow. In some embodiments,the primary catheter, channel catheter and steerable navigation catheterare moved through the patient, organ, lumen, and/or tissue via thesteerable tip of the steerable navigation catheter and/or steeringmechanisms within the primary catheter. In some embodiments, the channelcatheter and steerable navigation catheter are extended beyond the endof the primary catheter to access smaller, deeper, and/or more difficultto access tissue regions (e.g. peripheral bronchi, bronchioles, etc.).In some embodiments, the channel catheter and steerable navigationcatheter are moved through the patient, organ, lumen, and/or tissue viathe steerable tip of the steerable navigation catheter. In someembodiments, the position of the channel catheter and steerablenavigation catheter are monitored via the position sensor of thesteerable navigation catheter. In some embodiments, the distal ends ofthe channel catheter and steerable navigation catheter are placed at thetarget site (e.g. treatment site) in the patient, organ, lumen, and/ortissue (e.g. peripheral bronchi of the lung, peripheral lung nodule,etc.). In some embodiments, upon proper placement of the distal ends ofthe channel catheter and steerable navigation catheter at the targetsite (e.g. treatment site), the channel catheter (e.g. distal end of thechannel catheter) is secured into position. In some embodiments, thedistal end of the channel catheter is secured in proper place using anysuitable stabilization mechanism (e.g. screws, clips, wings, etc.), asis understood in the art. In some embodiments, upon proper placement ofthe distal ends of the channel catheter and steerable navigationcatheter at the target site (e.g. treatment site), the steerablenavigation catheter is withdrawn through the channel catheter and outthe proximal end of the channel catheter. In some embodiments,withdrawing the steerable catheter from the proximal end of the channelcatheter leaves the channel catheter in place as a channel for accessingthe target site (e.g. treatment site) with any suitable insertable tools(e.g. therapeutic tools (e.g. energy delivery device, biopsy device,etc.), etc.). In some embodiments, a properly positioned and securedchannel catheter with the steerable navigation catheter removedcomprises a guide channel for accessing the target site (e.g. peripheralbronchi of the lung) with insertable tools (e.g. energy delivery device,biopsy device, etc.) from outside a subject's body. In some embodiments,one or more insertable tools (e.g. therapeutic tools (e.g. energydelivery device, biopsy device, etc.) are inserted through the vacantchannel catheter (e.g. guide channel) and the distal tip of theinsertable tool is placed at the target site (e.g. treatment site). Insome embodiments, an energy delivery device (e.g. microwave ablationdevice) is inserted through the vacant channel catheter (e.g. guidechannel) and the distal tip of the energy delivery device is placed atthe target site (e.g. treatment site). In some embodiments, energy (e.g.microwave energy) is delivered through the channel catheter via theinserted energy delivery device to delivery energy to the target site(e.g. to ablate tissue at the target site).

In some embodiments, the present invention provides a method forsteering a catheter through a branched structure to a target location,comprising: (a) providing a steerable navigation catheter, wherein thesteerable navigation catheter comprises a position sensor elementlocated near a distal tip of the catheter, the position sensor elementbeing part of a system measuring a position and a pointing direction ofthe tip of the catheter relative to a three-dimensional frame ofreference; (b) designating the target location relative to thethree-dimensional frame of reference; (c) advancing the catheter intothe branched structure; and (d) displaying a representation of at leastone parameter defined by a geometrical relation between the pointingdirection of the tip of the catheter and a direction from the tip of thecatheter towards the target location. In some embodiments, the steerablenavigation catheter resides in the lumen of a channel catheter. In someembodiments, the steerable navigation catheter directs the movement ofthe channel catheter by the above mechanism. In some embodiments, thesteerable navigation catheter and channel catheter reside in the lumenof a primary catheter (e.g. bronchoscope). In some embodiments, thesteerable navigation catheter directs the movement of the channelcatheter and primary catheter by the above mechanism. In someembodiments, a primary catheter has a separate direction control(steering) mechanism from the steerable navigation catheter.

In some embodiments, a representation of at least one parameter definedby a geometrical relation between (i) the pointing direction of the tipof the steerable navigation catheter and (ii) a direction from the tipof the steerable navigation catheter towards the target location isdisplayed (e.g. to provide users with information regarding the positionand/or direction of the steerable navigation catheter). In someembodiments, the at least one parameter includes an angular deviationbetween the pointing direction of the tip of the steerable navigationcatheter and a direction from the tip of the steerable navigationcatheter towards the target location. In some embodiments, the at leastone parameter includes a direction of deflection required to bring thepointing direction of the steerable navigation catheter into alignmentwith the target location. In some embodiments, the representation of atleast one parameter is displayed in the context of a representation of aview taken along the pointing direction of the tip of the steerablenavigation catheter. In some embodiments, the position sensor element ispart of a six-degrees-of-freedom position measuring system measuring theposition and attitude of the tip of the steerable navigation catheter inthree translational and three rotational degrees of freedom. In someembodiments, the steerable navigation catheter is further provided witha multi-directional steering mechanism configured for selectivelydeflecting a distal portion of the catheter in any one of at least threedifferent directions. In some embodiments, the steering mechanism iscontrolled by a user via a control device at the proximal end of thesteerable navigation catheter. In some embodiments, the steeringmechanism is controlled by a user via a remote control device. In someembodiments, a path traveled by the tip of the steerable navigationcatheter is monitored by use of the position sensor element and arepresentation of the path traveled is displayed together with a currentposition of the tip, the representation being projected as viewed fromat least one direction non-parallel to the pointing direction of thetip.

In some embodiments, the target location (e.g. treatment location (e.g.tumor)) is designated by: (a) designating a target location by use ofcomputerized tomography data of a subject; and (b) registering thecomputerized tomography data with the three-dimensional frame ofreference. In some embodiments, other mapping data (e.g. MM, x-ray, PET,etc.) is substituted for computerized tomography data in any embodimentsof the present invention described herein. In some embodiments, theregistering is performed by: (a) providing the steerable catheter with acamera; (b) generating a camera view of each of at least threedistinctive features within the subject; (c) generating from thecomputerized tomography data a simulated view of each of the at leastthree distinctive features, each camera view and a corresponding one ofthe simulated views constituting a pair of similar views; (d) allowingan operator to designate a reference point viewed within each of thecamera views and a corresponding reference point viewed within eachcorresponding simulated view; and (e) deriving from the designatedreference points a best fit registration between the computerizedtomography data and the three-dimensional frame of reference. In someembodiments, an intended route through a subject (e.g. through abranched structure (e.g. a lung structure (e.g. bronchi)) within asubject) to a target location is designated by use of the computerizedtomography data and a representation of the intended route is displayedtogether with a current position of the tip, the representation beingprojected as viewed from at least one direction non-parallel to thepointing direction of the tip. In some embodiments: (a) a currentposition of the position sensor element is detected; (b) a virtualendoscopy image is generated from the computerized tomography datacorresponding to an image that would be viewed by a camera located inpredefined spatial relationship and alignment relative to the positionsensor element; and (c) displaying the virtual endoscopy image.

In some embodiments, a catheter system of the present inventioncomprises a steerable navigation catheter and a channel catheter havinga lumen extending from a proximal insertion opening to a distal opening;and a guide element configured for insertion through the proximalopening of the sheath to an inserted position extending along the lumento the distal opening. In some embodiments, a channel catheter is asheath, through which a steerable navigation catheter (or an energydelivery device) can be inserted and/or withdrawn. In some embodiments,the steerable navigation catheter is used to position the channelcatheter such that the distal tips of the steerable navigation catheterand channel catheter are adjacent to the target location (e.g. treatmentsite (e.g. tumor)). In some embodiments, the channel catheter is lockedinto proper position at the target location. In some embodiments, thesteerable navigation catheter is withdrawn from the channel lumenleaving an open channel extending from the point of insertion into thesubject to the target site. In some embodiments, the channel catheter isavailable for insertion of an insertable tool (e.g. medical tool (e.g.energy delivery device). In some embodiments, the present inventionprovides a method comprising: (a) guiding a steerable navigationcatheter within a channel catheter to a position with the tip adjacentto the target location; and (b) withdrawing the steerable navigationcatheter from the channel catheter to leave the channel lumen availablefor insertion of a medical tool (e.g. energy delivery device).

In some embodiments, a catheter system provides a primary catheter (e.g.flexible endoscope, flexible bronchoscope, etc.) having an operationhandle and a primary lumen, a channel catheter deployed within theprimary lumen and having a channel lumen, and a steerable navigationcatheter deployed within the channel lumen. In some embodiments, thepresent invention provides a method comprising: inserting the primarycatheter, housing the channel catheter and steerable navigationcatheter, into a subject, organ, tissue, and/or lumen until the primarycatheter reaches its maximum insertion distance (e.g. limited by sizefrom further insertion; (b) locking the steerable navigation catheterwithin the channel lumen to prevent movement of the steerable navigationcatheter relative to the channel catheter; (c) guiding the steerablenavigation catheter and channel catheter beyond the distal end of theprimary catheter to the target location; (d) locking the channelcatheter within the primary lumen to prevent relative movement of thechannel catheter relative to the primary catheter and/or operationhandle; and (e) unlocking and withdrawing the steerable navigationelement from the channel catheter so as to leave the channel in place asa guide for inserting a tool (e.g. energy delivery device) to the targetlocation. In some embodiments, a system or device of the presentinvention comprises a stabilization and/or anchoring mechanism to holdone or more elements in place when deployed in a subject and/or bodyregion. In some embodiments, a selectively actuatable anchoringmechanism is associated with a portion of the channel catheter. In someembodiments, the selectively actuatable anchoring mechanism includes aninflatable element. In some embodiments, the selectively actuatableanchoring mechanism includes a mechanically deployed element.

In some embodiments, a channel catheter and/or steerable navigationcatheter includes an image sensor deployed for generating an image inthe pointing direction of the catheter. In some embodiments, the imagesensor is configured to be withdrawn with the steerable navigationcatheter.

In some embodiments, the present invention provides a method forachieving registration between computerized tomography data (or othermapping data, e.g., MRI, PET, X-ray, etc.) and a three dimensional frameof reference of a position measuring system, the method comprising: (a)providing a catheter with: (i) a position sensor element which operatesas part of the position measuring system to allow measurement of aposition and a pointing direction of the tip of the catheter relative tothe three-dimensional frame of reference, and (ii) an image sensor; (b)generating from the computerized tomography data at least threesimulated views of distinctive features within the branched structure;(c) generating at least three camera views of the distinctive features,each camera view and a corresponding one of the simulated viewsconstituting a pair of similar views; (d) allowing an operator todesignate a reference point viewed within each of the camera views and acorresponding reference point viewed within each corresponding simulatedview; and (e) deriving from the designated reference points a best fitregistration between the computerized tomography image and thethree-dimensional frame of reference. In some embodiments, designationof a reference point within each of the camera views by the operator isperformed by the operator bringing the position sensor element intoproximity with the reference point. In some embodiments, designation ofa reference point within each simulated view by the operator isperformed by: (a) the operator selecting a simulated image referencepoint within each simulated view; (b) calculating from the simulatedimage reference point a simulated-viewing-point-to-reference-pointvector; and (c) calculating a point of intersection between thesimulated-viewing-point-to-reference-point vector and a tissue surfacein a numerical model of a portion of the body derived from thecomputerized tomography data. In some embodiments: (a) at least onelocation within the computerized tomography data is identified; (b) aposition of the at least one location is calculated within thethree-dimensional frame of reference; and (c) a representation of the atleast one location is displayed together with a representation of aposition of the position sensor element. In some embodiments, the atleast one location includes a target location (e.g. treatment location(e.g. tumor, bronchi (e.g. peripheral bronchi), etc.)) to which amedical tool (e.g. energy delivery device (e.g. microwave ablationdevice), etc.) is to be directed. In some embodiments, the at least onelocation is a series of locations defining a planned path along which amedical tool is to be directed. In some embodiments, a method forachieving registration between computerized tomography data and a threedimensional frame of reference of a position measuring system, themethod comprising: (a) providing a steerable navigation catheter with:(i) a position sensor element which operates as part of the positionmeasuring system to allow measurement of a position and a pointingdirection of the tip of the catheter relative to the three-dimensionalframe of reference, and (ii) an image sensor; (b) moving the tip of thecatheter along a first branch portion of a branched structure andderiving a plurality of images from the camera, each image beingassociated with corresponding position data of the position sensor inthe three dimensional frame of reference; (c) processing the images andcorresponding position data to derive a best-fit of a predefinedgeometrical model to the first branch portion in the three dimensionalframe of reference; (d) repeating steps (b) and (c) for a second branchportion of the branched structure; and (e) correlating the geometricalmodels of the first and second branch portions with the computerizedtomography data to derive a best fit registration between thecomputerized tomography data and the three dimensional frame ofreference. In some embodiments, the processing the images andcorresponding position data includes: (a) identifying visible featureseach of which is present in plural images taken at different positions;(b) for each of the visible features, deriving a camera-to-featuredirection in each of a plurality of the images; (c) employing thecamera-to-feature directions and corresponding position data todetermine a feature position for each visible feature; and (d) derivinga best-fit of the predefined geometrical model to the feature positions.In some embodiments, the predefined geometrical model is a cylinder. Insome embodiments: (a) at least one location within the computerizedtomography data is identified; (b) a position of the at least onelocation within the three-dimensional frame of reference is calculated;and (c) a representation of the at least one location is displayedtogether with a representation of a position of the position sensorelement. In some embodiments, the at least one location includes atarget location (e.g. treatment location (e.g. tumor (e.g. tumor in theperipheral bronchi))) to which a medical tool (e.g. energy deliverydevice (e.g. microwave ablation device) is to be directed. In someembodiments, the at least one location is a series of locations defininga planned path along which a medical tool is to be directed.

In some embodiments, the present invention provides a steering mechanismfor selectively deflecting a distal portion of a steerable navigationcatheter in any one of at least two independent directions, themechanism comprising: (a) at least three elongated tensioning elementsextending along the catheter and configured such that tension applied toany one of the tensioning elements causes deflection of a tip of thecatheter in a corresponding predefined direction; (b) an actuatordisplaceable from a first position to a second position; and (c) aselector mechanism configured for selectively mechanicallyinterconnecting a selected at least one of the elongated tensioningelements and the actuator such that displacement of the actuator fromthe first position to the second position applies tension to theselected at least one of the elongated tensioning elements. In someembodiments, a first state of the selector mechanism mechanicallyinterconnects a single one of the elongated tensioning elements with theactuator such that displacement of the actuator generates deflection ofthe tip in one of the predefined directions, and a second state of theselector mechanism mechanically interconnects two of the elongatedtensioning elements with the actuator such that displacement of theactuator generates deflection of the tip in an intermediate directionbetween two of the predefined directions. In some embodiments, the atleast three tensioning elements includes an even number of thetensioning elements, pairs of the tensioning elements being implementedas a single elongated element extending from the selector mechanismalong the catheter to the tip and back along the steerable navigationcatheter to the selector mechanism. In some embodiments, the at leastthree tensioning elements is implemented as four tensioning elementsdeployed such that each tensioning element, when actuated alone, causesdeflection of the tip in a different one of four predefined directionsseparated substantially by multiples of 90°. In some embodiments, afirst state of the selector mechanism mechanically interconnects asingle one of the elongated tensioning elements with the actuator suchthat displacement of the actuator generates deflection of the tip in oneof the four predefined directions, and a second state of the selectormechanism mechanically interconnects two of the elongated tensioningelements with the actuator such that displacement of the actuatorgenerates deflection of the tip in one of four intermediate directionseach lying between two of the four predefined directions. In someembodiments, the actuator includes a ring which is slidable relative toa handle associated with the catheter, and wherein the selectormechanism includes a slide attached to each of the tensioning elementsand slidably deployed within the handle and at least one projectionprojecting from the ring such that, when the ring is rotated, the atleast one projection selectively engages at least one of the slides suchthat displacement of the ring causes movement of the at least one slide.

In some embodiments, the present invention provides devices, systems,and methods for reducing overheating during energy delivery to tissuesin a subject. One significant source of undesired overheating of thedevice is the dielectric heating of the insulator (e.g., the coaxialinsulator), potentially resulting in collateral tissue damage. Theenergy delivery devices of the present invention are designed to preventundesired overheating. The energy delivery devices are not limited to aparticular manner of preventing undesired device heating. In someembodiments, the devices employ circulation of coolant. In someembodiments, the devices are configured to detect an undesired rise intemperature within the device (e.g., along the outer conductor) andautomatically or manually reduce such an undesired temperature risethrough flowing of coolant through coolant passage channels. In someembodiments, devices employ a porous insulator as a dielectric material,thereby allowing coolant to flow through the dielectric material. Insome embodiments, one or more coolant channels provide a means forreducing heat loss from transmission lines to the surrounding tissue. Insome embodiments, constant low-power or pulsed high-power energy isdelivered to reduce overheating. In some embodiments, coolant channelsrun through the dielectric material. In some embodiments, coolant servesas a dielectric material. In some embodiments, the dielectric space isall or partially filled with coolant material.

In some embodiments, the energy delivery devices have improved coolingcharacteristics. For example, in some embodiments, the devices permitthe use of coolant without increasing the diameter of the device. Thisis in contrast to existing devices that flow coolant through an externalsleeve or otherwise increase the diameter of the device to accommodatethe flow of a coolant. In some embodiments, the energy delivery deviceshave therein one or more coolant passage channels for purposes ofreducing unwanted heat dissipation (see, e.g., U.S. patent applicationSer. No. 11/728,460; herein incorporated by reference in its entirety).In some embodiments, energy delivery devices have therein a tube (e.g.,needle, plastic tube, etc.) that runs the length of or partially runsthe length of the device, designed to prevent device overheating throughcirculation of coolant material. In some embodiments, channels or tubesdisplace material from a dielectric component located between the innerand outer conductors of a coaxial cable. In some embodiments, coolantmaterial (e.g. air, CO₂, etc.) is the dielectric material. In someembodiments, coolant material comprises all or part of the dielectricspace (e.g. the space between the inner conductor and outer conductor ofa coaxial transmission line). In some embodiments, channels or tubesreplace the dielectric material or substantially replace the dielectricmaterial. In some embodiments, a porous dielectric material is used toaccommodate the flow of coolant through the dielectric material. In someembodiments, channel or tubes displace a portion of the outer conductor.For example, in some embodiments, a portion of the outer conductor isremoved or shaved off to generate a passageway for the flow of coolant.One such embodiment is shown in FIG. 12. A coaxial cable 900 has anouter conductor 910, an inner conductor 920, and a dielectric material930. A region 940 of the outer conductor is removed, creating space forcoolant flow. The only remaining outer conductor material circumscribesor substantially circumscribes the coaxial cable is at distal 950 andproximal 960 end regions. A thin strip of conductive material 970connects the distal 950 and proximal 960 end regions. A thin channel 980is cut from the conductive material at the proximal end region 960 topermit coolant flow into the region where the outer conductive materialwas removed (or was manufacture to be absent) 940. The present inventionis not limited by the size or shape of the passageway, so long ascoolant can be delivered. For example, in some embodiments, thepassageway is a linear path that runs the length of the coaxial cable.In some embodiments, spiral channels are employed. In some embodiments,the tube or channel displaces or replaces at least a portion of theinner conductor. For example, large portions of the inner conductor maybe replaced with a coolant channel, leaving only small portions of metalnear the proximal and distal ends of the device to permit tuning,wherein the portions are connected by a thin strip of conductingmaterial. In some embodiments, a region of interior space is createdwithin the inner or outer conductor to create one or more channels forcoolant. For example, the inner conductor may be provided as a hollowtube of conductive material, with a coolant channel provided in thecenter. In such embodiments, the inner conductor can be used either forinflow or outflow (or both) of coolant. In some embodiments, a coolantchannel displaces a portion of the dielectric material. In someembodiments, channels are formed by gaps within the dielectric material.

In some embodiments in which a coolant tube is placed within the device,the tube has multiple channels for intake and outtake of coolant throughthe device. The device is not limited to a particular positioning of thetube (e.g., coolant needle) within the dielectric material. In someembodiments, the tube is positioned along the outside edge of thedielectric material, the middle of the dielectric material, or at anylocation within the dielectric material. In some embodiments, thedielectric material is pre-formed with a channel designed to receive andsecure the tube. In some embodiments, a handle is attached with thedevice, wherein the handle is configured to, for example, control thepassing of coolant into and out of the tube. In some embodiments, thetube is flexible. In some embodiments, the tube is inflexible (e.g.regions of inflexibility). In some embodiments, the portions of the tubeare flexible, while other portions are inflexible. In some embodiments,the tube is compressible. In some embodiments, the tube isincompressible. In some embodiments, portions of the tube arecompressible, while other portions are incompressible. The tube is notlimited to a particular shape or size. In some embodiments, wherein thetube is a coolant needle (e.g., a 29 gauge needle or equivalent size)that fits within a coaxial cable having a diameter equal or less than a12 gauge needle. In some embodiments, the exterior of the tube has acoating of adhesive and/or grease so as to secure the tube or permitsliding movement within the device. In some embodiments, the tube hasone or more holes along its length that permit release of coolant intodesired regions of the device. In some embodiments, the holes areinitially blocked with a meltable material, such that a particularthreshold of heat is required to melt the material and release coolantthrough the particular hole or holes affected. As such, coolant is onlyreleased in areas that have reached the threshold heat level.

In some embodiments, coolant is preloaded into the antenna, handle orother component of the devices of the present invention. In otherembodiments, the coolant is added during use. In some pre-loadedembodiments, a liquid coolant is preloaded into, for example, the distalend of the antenna under conditions that create a self-perpetuatingvacuum. In some such embodiments, as the liquid coolant vaporizes, morefluid is drawn in by the vacuum.

The present invention is not limited by the nature of the coolantmaterial employed. Coolants included, but are not limited to, liquidsand gases. Exemplary coolant fluids include, but are not limited to, oneor more of or combinations of, water, glycol, air, inert gasses, carbondioxide, nitrogen, helium, sulfur hexafluoride, ionic solutions (e.g.,sodium chloride with or without potassium and other ions), dextrose inwater, Ringer's lactate, organic chemical solutions (e.g., ethyleneglycol, diethylene glycol, or propylene glycol), oils (e.g., mineraloils, silicone oils, fluorocarbon oils), liquid metals, freons,halomethanes, liquified propane, other haloalkanes, anhydrous ammonia,sulfur dioxide. In some embodiments, the coolant fluid also serves asthe dielectric material. In some embodiments, the coolant is a gascompressed at or near its critical point. In some embodiments, coolingoccurs, at least in part, by changing concentrations of coolant,pressure, or volume. For example, cooling can be achieved via gascoolants using the Joule-Thompson effect. In some embodiments, thecooling is provided by a chemical reaction. The devices are not limitedto a particular type of temperature reducing chemical reaction. In someembodiments, the temperature reducing chemical reaction is anendothermic reaction. The devices are not limited to a particular mannerof applying endothermic reactions for purposes of preventing undesiredheating. In some embodiments, first and second chemicals are flowed intothe device such that they react to reduce the temperature of the device.In some embodiments, the device is prepared with the first and secondchemicals preloaded in the device. In some embodiments, the chemicalsare separated by a barrier that is removed when desired. In someembodiments, the barrier is configured to melt upon exposure to apredetermined temperature or temperature range. In such embodiments, thedevice initiates the endothermical reaction only upon reaching a heatlevel that merits cooling. In some embodiments, multiple differentbarriers are located throughout the device such that local coolingoccurs only at those portions of the device where undesired heating isoccurring. In some embodiment, the barriers used are beads thatencompass one of the two chemicals. In some embodiments, the barriersare walls (e.g., discs in the shape of washers) that melt to combine thetwo chemicals. In some embodiments, the barriers are made of wax that isconfigured to melt at a predetermined temperature. The devices are notlimited to a particular type, kind or amount of meltable material. Insome embodiments, the meltable material is biocompatible. The devicesare not limited to a particular type, kind, or amount of first andsecond chemicals, so long as their mixture results in a temperaturereducing chemical reaction. In some embodiments, the first materialincludes barium hydroxide octahydrate crystals and the second materialis dry ammonium chloride. In some embodiments, the first material iswater and the second material is ammonium chloride. In some embodiments,the first material is thionyl chloride (SOCl₂) and the second materialis cobalt(II) sulfate heptahydrate. In some embodiments, the firstmaterial is water and the second material is ammonium nitrate. In someembodiments, the first material is water and the second material ispotassium chloride. In some embodiments, the first material is ethanoicacid and the second material is sodium carbonate. In some embodiments, ameltable material is used that, itself, reduces heat by melting anflowing in a manner such that the heat at the outer surface of thedevice is reduced.

In some embodiments, the energy delivery devices prevent undesiredheating and/or maintain desired energy delivery properties throughadjusting the amount of energy emitted from the device (e.g., adjustingthe energy wavelength resonating from the device) as temperaturesincrease. The devices are not limited to a particular method ofadjusting the amount of energy emitted from the device. In someembodiments, the devices are configured such that as the device reachesa certain threshold temperature or as the device heats over a range, theenergy wavelength resonating from the device is adjusted. The devicesare not limited to a particular method for adjusting energy wavelengthresonating from the device. In some embodiments, the device has thereina material that changes in volume as the temperature increases. Thechange in volume is used to move or adjust a component of the devicethat affects energy delivery. For example, in some embodiments, amaterial is used that expands with increasing temperature. The expansionis used to move the distal tip of the device outward (increasing itsdistance from the proximal end of the device), altering the energydelivery properties of the device. This finds particular use with thecenter-fed dipole embodiments of the present invention. In someembodiments, the energy delivery devices prevent undesired heatingand/or maintain desired energy delivery properties through adjusting theenergy delivery program without lowering the energy wavelength. In someembodiments, pulsed programs deliver bursts of energy to the treatmentsite (e.g. bursts of energy sufficient to perform the desired task (e.g.ablation)) without inducing undesired heating along the transmissionpath. In some embodiments, pulsed programs reduce heat along thetransmission pathway when compared to continuous delivery programs. Insome embodiments, different patterns of pulse programs effectivelybalance the potentially conflicting desires of large amounts of energydelivered to the treatment site and reduced heat along the deliverypath. In some embodiments, different pulse patterns (e.g. length of timedelivering energy, length of time between energy pulses) and differentenergy levels (e.g. energy wavelengths) are utilized to optimizeenergy-delivery and path-heating.

In certain embodiments, the present invention provides a devicecomprising an antenna configured for delivery of energy to a tissue,wherein a distal end of the antenna comprises a center-fed dipolecomponent comprising a rigid hollow tube encompassing a conductor,wherein a stylet is secured within the hollow tube. In some embodiments,the hollow tube has a diameter equal to or less than a 20-gauge needle.In some embodiments, the hollow tube has a diameter equal to or lessthan a 17-gauge needle. In some embodiments, the hollow tube has adiameter equal to or less than a 12-gauge needle. In some embodiments,the device further comprises a tuning element for adjusting the amountof energy delivered to the tissue. In some embodiments, the device isconfigured to deliver a sufficient amount of energy to ablate the tissueor cause thrombosis. In some embodiments, the conductor extends halfwaythrough the hollow tube. In some embodiments, the hollow tube has alength λ/2, wherein λ is the electromagnetic field wavelength in themedium of the tissue. In some embodiments, an expandable material ispositioned near the stylet such that as the device increases intemperature the expandable material expands and pushes onto the styletmoving the stylet and changes the energy delivery properties of thedevice. In some embodiments, the expandable material is positionedbehind (proximal to) a metal disc that provides the resonant element forthe center-fed dipole device. As the material expands, the disc ispushed distally, adjusting the tuning of the device. The expandablematerial is preferably selected so that the rate of expansion coincideswith a desired change in energy delivery for optimal results. However,it should be understood that any change in the desired directions findsuse with the invention. In some embodiments, the expandable material iswax.

In some embodiments, the device has a handle attached with the device,wherein the handle is configured to, for example, control the passing ofcoolant into and out of coolant channels. In some embodiments, only thehandle is cooled. In some embodiments, the handle is configured todeliver a gaseous coolant compressed at or near its critical point. Inother embodiments, the handle and an attached antenna are cooled. Insome embodiments, the handle automatically passes coolant into and outof the coolant channels after a certain amount of time and/or as thedevice reaches a certain threshold temperature. In some embodiments, thehandle automatically stops passage of coolant into and out of thecoolant channels after a certain amount of time and/or as thetemperature of the device drops below a certain threshold temperature.In some embodiments, coolant flowed through the handle is manuallycontrolled. In some embodiments, the handle has thereon one or more(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., display lights(e.g., LED lights)). In some embodiments, the lights are configured tofor identification purposes. For example, in some embodiments, thelights are used to differentiate between different probes (e.g.,activation of a first probe displays one light; a second probe twolights, a third probe three lights, or each probe has its own designatedlight, etc.). In some embodiments, the lights are used to identify theoccurrence of an event (e.g., the transmission of coolant through thedevice, the transmission of energy through the device, a movement of therespective probe, a change in a setting (e.g., temperature, positioning)within the device, etc.). The handles are not limited to a particularmanner of display (e.g., blinking, alternate colors, solid colors, etc).

In some embodiments, the energy delivery devices have therein a centerfed dipole component (see, e.g., U.S. patent application Ser. No.11/728,457; herein incorporated by reference in its entirety). In someembodiments, the energy delivery devices comprise a catheter withmultiple segments for transmitting and emitting energy (see, e.g., U.S.patent application Ser. Nos. 11/237,430, 11/237,136, and 11/236,985;each herein incorporated by reference in their entireties). In someembodiments, the energy delivery devices comprise a triaxial microwaveprobe with optimized tuning capabilities to reduce reflective heat loss(see, e.g., U.S. Pat. No. 7,101,369; see, also, U.S. patent applicationSer. Nos. 10/834,802, 11/236,985, 11/237,136, 11/237,430, 11/440,331,11/452,637, 11/502,783, 11/514,628; and International Patent ApplicationNo. PCT/US05/14534; herein incorporated by reference in its entirety).In some embodiments, the energy delivery devices emit energy through acoaxial transmission line (e.g., coaxial cable) having air or othergases as a dielectric core (see, e.g., U.S. patent application Ser. No.11/236,985; herein incorporated by reference in its entirety). In somesuch embodiments, materials that support the structure of the devicebetween the inner and outer conductors may be removed prior to use. Forexample, in some embodiments, the materials are made of a dissolvable ormeltable material that is removed prior to or during use. In someembodiments, the materials are meltable and are removed during use (uponexposure to heat) so as to optimize the energy delivery properties ofthe device over time (e.g., in response to temperature changes intissue, etc.).

The present invention is not limited to a particular coaxialtransmission line shape. Indeed, in some embodiments, the shape of thecoaxial transmission line and/or the dielectric element is adjustable tofit a particular need. In some embodiments, the cross-sectional shape ofthe coaxial transmission line and/or the dielectric element is circular.In some embodiments, the cross-sectional shape is non-circular (e.g.,oval, etc.). Such shapes may apply to the coaxial cable as a whole, ormay apply to one or more sub-components only. For example, an ovaldielectric material may be placed in a circular outer conductor. This,for example, has the advantage of creating two channels that may beemployed, for example, to circulate coolant. As another example,square/rectangular dielectric material may be placed in a circularconductor. This, for example, has the advantage of creating fourchannels. Different polygonal shapes in the cross-section (e.g.,pentagon, hexagon, etc.) may be employed to create different numbers andshapes of channels. The cross-sectional shape need not be the samethroughout the length of the cable. In some embodiments, a first shapeis used for a first region (e.g., a proximal region) of the cable and asecond shape is used for a second region (e.g., a distal region) of thecable. Irregular shapes may also be employed. For example, a dielectricmaterial having an indented groove running its length may be employed ina circular outer conductor to create a single channel of any desiredsize and shape. In some embodiments, the channel provides space forfeeding coolant, a needle, or other desired components into the devicewithout increasing the ultimate outer diameter of the device.

Likewise, in some embodiments, an antenna of the present invention has anon-circular cross-sectional shape along its length or for one or moresubsections of its length. In some embodiments, the antenna isnon-cylindrical, but contains a coaxial cable that is cylindrical. Inother embodiments, the antenna is non-cylindrical and contains a coaxialcable that is non-cylindrical (e.g., matching the shape of the antennaor having a different non-cylindrical shape). In some embodiments,having any one or more components (e.g., cannula, outer shell ofantenna, outer conductor of coaxial cable, dielectric material ofcoaxial cable, inner conductor of coaxial cable) possessing anon-cylindrical shape permits the creation of one or more channels inthe device that may be used, among other reasons, to circulate coolant.Non-circular shapes, particularly in the outer diameter of the antennaalso find use for certain medical or other applications. For example, ashape may be chosen to maximize flexibility or access to particularinner body locations. Shape may also be chosen to optimize energydelivery. Shape (e.g., non-cylindrical shape) may also be selected tomaximize rigidity and/or strength of the device, particularly for smalldiameter devices.

In certain embodiments, the present invention provides a devicecomprising an antenna, wherein the antenna comprises an outer conductorenveloped around an inner conductor, wherein the inner conductor isdesigned to receive and transmit energy, wherein the outer conductor hastherein at least one gap positioned circumferentially along the outerconductor, wherein multiple energy peaks are generated along the lengthof the antenna, the position of the energy peaks controlled by thelocation of the gap. In some embodiments, the energy is microwave energyand/or radiofrequency energy. In some embodiments, the outer conductorhas therein two of the gaps. In some embodiments, the antenna comprisesa dielectric layer disposed between the inner conductor and the outerconductor. In some embodiments, the dielectric layer has near-zeroconductivity. In some embodiments, the device further comprises astylet. In some embodiments, the inner conductor has a diameter ofapproximately 0.013 inches or less.

In some embodiments, any gaps or inconsistencies or irregularities inthe outer conductor or outer surface of the device are filled with amaterial to provide a smooth, even, or substantially smooth, even outersurface. In some embodiments, a heat-resistant, resin is used to fillgaps, inconsistencies, and/or irregularities. In some embodiments, theresin is biocompatible. In other embodiments, it is not biocompatible,but, for example, can be coated with a biocompatible material. In someembodiments, the resin is configurable to any desired size or shape. Assuch, the resin, when hardened, may be used to provide a sharp stylettip to the devices or any other desired physical shape.

In some embodiments, the device comprises a sharp stylet tip. The tipmay be made of any material. In some embodiments, the tip is made fromhardened resin. In some embodiments, the tip is metal. In some suchembodiments, the metal tip is an extension of a metal portion of anantenna and is electrically active. In some embodiments, the distal tipof a device comprises a cutting trocar.

In some embodiments, the energy delivery devices are configured todelivery energy to a tissue region within a system comprising aprocessor, a power supply, a means of directing, controlling anddelivering power (e.g., a power splitter with the capability ofindividual control of power delivery to each antenna), an imagingsystem, a tuning system, a temperature measurement adjustment system,and/or a device placement system.

The present invention is not limited to a particular type of processor.In some embodiments, the processor is designed to, for example, receiveinformation from components of the system (e.g., temperature monitoringsystem, energy delivery device, tissue impedance monitoring component,etc.), display such information to a user, and manipulate (e.g.,control) other components of the system. In some embodiments, theprocessor is configured to operate within a system comprising an energydelivery device, a power supply, a means of directing, controlling anddelivering power (e.g., a power splitter), an imaging system, a tuningsystem, and/or a temperature adjustment system.

The present invention is not limited to a particular type of powersupply. In some embodiments, the power supply is configured to provideany desired type of energy (e.g., microwave energy, radiofrequencyenergy, radiation, cryo energy, electroporation, high intensity focusedultrasound, and/or mixtures thereof). In some embodiments, the powersupply utilizes a power splitter to permit delivery of energy to two ormore energy delivery devices. In some embodiments, the power supply isconfigured to operate within a system comprising a power splitter, aprocessor, an energy delivery device, an imaging system, a tuningsystem, and/or a temperature adjustment system.

The present invention is not limited to a particular type of imagingsystem. In some embodiments, the imaging system utilizes imaging devices(e.g., endoscopic devices, stereotactic computer assisted neurosurgicalnavigation devices, thermal sensor positioning systems, motion ratesensors, steering wire systems, intraprocedural ultrasound, fluoroscopy,computerized tomography magnetic resonance imaging, nuclear medicineimaging devices triangulation imaging, interstitial ultrasound,microwave imaging, acoustic tomography, dual energy imaging,thermoacoustic imaging, infrared and/or laser imaging, electromagneticimaging) (see, e.g., U.S. Pat. Nos. 6,817,976, 6,577,903, and 5,697,949,5,603,697, and International Patent Application No. WO 06/005,579; eachherein incorporated by reference in their entireties). In someembodiments, the systems utilize endoscopic cameras, imaging components,and/or navigation systems that permit or assist in placement,positioning, and/or monitoring of any of the items used with the energysystems of the present invention. In some embodiments, the imagingsystem is configured to provide location information of particularcomponents of the energy delivery system (e.g., location of the energydelivery device). In some embodiments, the imaging system is configuredto operate within a system comprising a processor, an energy deliverydevice, a power supply, a tuning system, and/or a temperature adjustmentsystem. In some embodiments, the imaging system is located within theenergy delivery device. In some embodiments, the imaging system providesqualitative information about the ablation zone properties (e.g., thediameter, the length, the cross-sectional area, the volume). The imagingsystem is not limited to a particular technique for providingqualitative information. In some embodiments, techniques used to providequalitative information include, but are not limited to, time-domainreflectometry, time-of-flight pulse detection, frequency-modulateddistance detection, eigenmode or resonance frequency detection orreflection and transmission at any frequency, based on one interstitialdevice alone or in cooperation with other interstitial devices orexternal devices. In some embodiments, the interstitial device providesa signal and/or detection for imaging (e.g., electro-acoustic imaging,electromagnetic imaging, electrical impedance tomography).

The present invention is not limited to a particular tuning system. Insome embodiments, the tuning system is configured to permit adjustmentof variables (e.g., amount of energy delivered, frequency of energydelivered, energy delivered to one or more of a plurality of energydevices that are provided in the system, amount of or type of coolantprovided, etc.) within the energy delivery system. In some embodiments,the tuning system comprises a sensor that provides feedback to the useror to a processor that monitors the function of an energy deliverydevice continuously or at time points. The sensor may record and/orreport back any number of properties, including, but not limited to,heat (e.g., temperature) at one or more positions of a components of thesystem, heat at the tissue, property of the tissue, qualitativeinformation of the region, and the like. The sensor may be in the formof an imaging device such as CT, ultrasound, magnetic resonance imaging,fluoroscopy, nuclear medicine imaging, or any other imaging device. Insome embodiments, particularly for research application, the systemrecords and stores the information for use in future optimization of thesystem generally and/or for optimization of energy delivery underparticular conditions (e.g., patient type, tissue type, size and shapeof target region, location of target region, etc.). In some embodiments,the tuning system is configured to operate within a system comprising aprocessor, an energy delivery device, a power supply, an imaging, and/ora temperature adjustment system. In some embodiments, the imaging orother control components provide feedback to the ablation device so thatthe power output (or other control parameter) can be adjusted to providean optimum tissue response.

The present invention is not limited to a particular temperatureadjustment system. In some embodiments, the temperature adjustmentsystems are designed to reduce unwanted heat of various components ofthe system (e.g., energy delivery devices) during medical procedures(e.g., tissue ablation) or keep the target tissue within a certaintemperature range. In some embodiments, the temperature adjustmentsystems are configured to operate within a system comprising aprocessor, an energy delivery device, a power supply, a means ofdirecting, controlling and delivering power (e.g., a power splitter), atuning system, and/or an imaging system. In some embodiments, thetemperature adjustment system is designed to cool the energy deliverydevice to a temperature that is sufficient to temporarily adhere thedevice to internal patient tissue so as to prevent the energy devicefrom moving during a procedure (e.g., the ablation procedure).

In some embodiments, the systems further comprise temperature monitoringor reflected power monitoring systems for monitoring the temperature orreflected power of various components of the system (e.g., energydelivery devices) and/or a tissue region. In some embodiments, themonitoring systems are designed to alter (e.g., prevent, reduce) thedelivery of energy to a particular tissue region if, for example, thetemperature or amount of reflected energy, exceeds a predeterminedvalue. In some embodiments, the temperature monitoring systems aredesigned to alter (e.g., increase, reduce, sustain) the delivery ofenergy to a particular tissue region so as to maintain the tissue orenergy delivery device at a preferred temperature or within a preferredtemperature range.

In some embodiments, the systems further comprise an identification ortracking system configured, for example, to prevent the use ofpreviously used components (e.g., non-sterile energy delivery devices),to identify the nature of a component of the system so the othercomponents of the system may be appropriately adjusted for compatibilityor optimized function. In some embodiments, the system reads a bar codeor other information-conveying element associated with a component ofthe systems of the invention. In some embodiments, the connectionsbetween components of the system are altered (e.g., broken) followinguse so as to prevent additional uses. The present invention is notlimited by the type of components used in the systems or the usesemployed. Indeed, the devices may be configured in any desired manner.Likewise, the systems and devices may be used in any application whereenergy is to be delivered. Such uses include any and all medical,veterinary, and research applications. However, the systems and devicesof the present invention may be used in agricultural settings,manufacturing settings, mechanical settings, or any other applicationwhere energy is to be delivered.

In some embodiments, the systems are configured for percutaneous,intravascular, intracardiac, laparoscopic, or surgical delivery ofenergy. Likewise, in some embodiments, the systems are configured fordelivery of energy through a catheter, through a surgically developedopening, and/or through a body orifice (e.g., mouth, ear, nose, eyes,vagina, penis, anus) (e.g., a N.O.T.E.S. procedure). In someembodiments, the systems are configured for delivery of energy to atarget tissue or region. The present invention is not limited by thenature of the target tissue or region. Uses include, but are not limitedto, treatment of heart arrhythmia, tumor ablation (benign andmalignant), control of bleeding during surgery, after trauma, for anyother control of bleeding, removal of soft tissue, tissue resection andharvest, treatment of varicose veins, intraluminal tissue ablation(e.g., to treat esophageal pathologies such as Barrett's Esophagus andesophageal adenocarcinoma), treatment of bony tumors, normal bone, andbenign bony conditions, intraocular uses, uses in cosmetic surgery,treatment of pathologies of the central nervous system including braintumors and electrical disturbances, sterilization procedures (e.g.,ablation of the fallopian tubes) and cauterization of blood vessels ortissue for any purposes. In some embodiments, the surgical applicationcomprises ablation therapy (e.g., to achieve coagulative necrosis). Insome embodiments, the surgical application comprises tumor ablation totarget, for example, metastatic tumors. In some embodiments, the deviceis configured for movement and positioning, with minimal damage to thetissue or organism, at any desired location, including but not limitedto, the brain, neck, chest, lung (e.g. peripheral lung), abdomen, andpelvis. In some embodiments, the systems are configured for guideddelivery, for example, by computerized tomography, ultrasound, magneticresonance imaging, fluoroscopy, and the like.

In certain embodiments, the present invention provides methods oftreating a tissue region, comprising: providing a tissue region and asystem described herein (e.g., an energy delivery device, and at leastone of the following components: a processor, a power supply, a means ofdirecting, controlling and delivering power (e.g., a power splitter), atemperature monitor, an imager, a tuning system, a temperature reductionsystem, and/or a device placement system); positioning a portion of theenergy delivery device in the vicinity of the tissue region, anddelivering an amount of energy with the device to the tissue region. Insome embodiments, the tissue region is a tumor. In some embodiments, thedelivering of the energy results in, for example, the ablation of thetissue region and/or thrombosis of a blood vessel, and/orelectroporation of a tissue region. In some embodiments, the tissueregion is a tumor. In some embodiments, the tissue region comprises oneor more of the heart, liver, genitalia, stomach, lung (e.g. periphery ofthe lung), large intestine, small intestine, brain, neck, bone, kidney,muscle, tendon, blood vessel, prostate, bladder, spinal cord, skin,veins, finger nails, and toe nails. In some embodiments, the processorreceives information from sensors and monitors and controls the othercomponents of the systems. In some embodiments, the energy output of thepower supply is altered, as desired, for optimized therapy. In someembodiments, where more than one energy delivery component is provided,the amount of energy delivered to each of the delivery components isoptimized to achieve the desired result. In some embodiments, thetemperature of the system is monitored by a temperature sensor and, uponreaching or approaching a threshold level, is reduced by activation ofthe temperature reduction system. In some embodiments the imaging systemprovides information to the processor, which is displayed to a user ofthe system and may be used in a feedback loop to control the output ofthe system.

In some embodiments, energy is delivered to the tissue region indifferent intensities and from different locations within the device.For example, certain regions of the tissue region may be treated throughone portion of the device, while other regions of the tissue may betreated through a different portion of the device. In addition, two ormore regions of the device may simultaneously deliver energy to aparticular tissue region so as to achieve constructive phaseinterference (e.g., wherein the emitted energy achieves a synergisticeffect). In other embodiments, two or more regions of the device maydeliver energy so as to achieve a destructive interference effect. Insome embodiments, the method further provides additional devices forpurposes of achieving constructive phase interference and/or destructivephase interference. In some embodiments, phase interference (e.g.,constructive phase interference, destructive phase interference),between one or more devices, is controlled by a processor, a tuningelement, a user, and/or a power splitter.

The systems, devices, and methods of the present invention may be usedin conjunction with other systems, device, and methods. For example, thesystems, devices, and methods of the present invention may be used withother ablation devices, other medical devices, diagnostic methods andreagents, imaging methods and reagents, device placement systems, andtherapeutic methods and agents. Use may be concurrent or may occurbefore or after another intervention. The present invention contemplatesthe use systems, devices, and methods of the present invention inconjunction with any other medical interventions.

Additionally, integrated ablation and imaging systems are needed thatprovide feedback to a user and permit communication between varioussystem components. System parameters may be adjusted during the ablationto optimize energy delivery. In addition, the user is able to moreaccurately determine when the procedure is successfully completed,reducing the likelihood of unsuccessful treatments and/or treatmentrelated complications.

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the tubes configured to deliver coolant to the antenna,wherein the coolant is a gas compressed at or near its critical point.In some embodiments, the coolant comprises the dielectric material ofthe coaxial cable. In some embodiments, the coolant channels comprisesall or part of the dielectric space. The devices are not limited to aparticular gas. In some embodiments, the gas is CO₂. In someembodiments, the one or more coolant tubes or channels are between anouter conductor and dielectric material of the coaxial cable. In someembodiments, the one or more coolant tubes or channels are between aninner conductor and dielectric material of the coaxial cable. In someembodiments, a porous dielectric material allows coolant to be floweddirectly through the dielectric material. In some embodiments, the oneor more coolant tubes or channels are within an inner or outerconductor. In some embodiments, the device has therein a proximalregion, a central region, and a distal region. In some embodiments, thedistal region is configured to deliver the energy to the tissue. In someembodiments, the proximal and/or central regions have therein thecoolant tubes or channels. In some embodiments, the distal portion doesnot have the coolant tubes or channels.

In some embodiments, the device has therein one or more “stick” regionsconfigured to facilitate adherence of the tissue onto the stick region,for example, to stabilize the device in a desired position during energydelivery. In some embodiments, the stick region is configured to attainand maintain a temperature causing freezing of the tissue to the stickregion. In some embodiments, the stick region is positioned within thecentral region and/or the proximal region. The stick region is notlimited to any particular temperature for facilitating adherence of atissue region. In some embodiments, the stick region attains andmaintains a temperature for facilitating adherence of a tissue regionthrough contacting a region of the energy delivery device havingcirculated coolant. In some embodiments, the temperature of the stickregion is maintained at temperature low enough such that adherence of atissue region occurs upon contact with the stick region (e.g., such thata tissue region freezes onto the stick region). The stick region is notlimited to a particular material composition. In some embodiments, thestick region is, for example, a metal material, a ceramic material, aplastic material, and/or any combination of such substances.

In some embodiments, the distal region and the central region areseparated by a plug region designed to prevent cooling of the distalregion. The plug region is not limited to a particular manner ofpreventing cooling of the distal region. In some embodiments, the plugregion is designed to be in contact with a region having a reducedtemperature (e.g., the central region of the energy delivery devicehaving circulated coolant) without having its temperature reduced. Insome embodiments, the material of the plug region is such that it isable to be in contact with a material having a low temperature withouthaving its temperature substantially reduced (e.g., an insulatingmaterial). The plug region is not limited to a particular type ofinsulating material (e.g., a synthetic polymer (e.g., polystyrene,polyicynene, polyurethane, polyisocyanurate), aerogel, fibre-glass,cork). In some embodiments, a device having a plug region permitssimultaneous exposure of a tissue to a cooled region (e.g., the regionof the device proximal to the plug region) and an uncooled region (e.g.,the region of the device distal to the plug region).

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the coaxial cable having a dielectric region, thedielectric region having flexible and inflexible regions. In someembodiments, the flexible region is plastic, and the inflexible regionis ceramic. In some embodiments, the inflexible region is positioned atthe location of highest power emission.

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the device having therein one or more pullwires connectedto a pullwire anchor. In some embodiments, contraction of the one ormore pullwires connected to the pullwire anchor reduces flexibility ofthe device. In some embodiments, the one or more pullwires are designedto bend at particular temperatures (e.g., super elastic nitinol wires).

In some embodiments, the present invention provides systems, devices,and methods for delivering energy (e.g. microwave energy) to a treatmentsite in a subject. In some embodiments, the present invention providesmethods to deliver energy to difficult to access regions of a subject.In some embodiments, the present invention provides access to theperipheral lung through the bronchial tree. In some embodiments, thepresent invention provides access to lung nodules, tumors, and/orlesions on peripheral lung tissue (e.g. without incision into the lung)or without entry from the outside of the lung. In some embodiments, thepresent invention provides access to lung nodules, tumors, and/orlesions on peripheral lung tissue through the trachea and/or bronchialtree (e.g. primary, secondary, and tertiary bronchia, and bronchioles).In some embodiments, the present invention delivers energy (e.g.microwave energy) through the bronchial tree to the peripheral lungwithout damaging (e.g. without significantly damaging the tissue alongthe path).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of an energy delivery system in anembodiment of the invention.

FIG. 2 shows various shapes of coaxial transmission lines and/or thedielectric elements in some embodiments of the present invention.

FIGS. 3A and 3B display a coaxial transmission line embodiment havingpartitioned segments with first and second materials blocked by meltablewalls for purposes of preventing undesired device heating (e.g., heatingalong the outer conductor).

FIGS. 4A and 4B display a coaxial transmission line embodiment havingpartitioned segments segregated by meltable walls containing first andsecond materials (e.g., materials configured to generate a temperaturereducing chemical reaction upon mixing) preventing undesired deviceheating (e.g., heating along the outer conductor).

FIG. 5 shows a schematic drawing of a handle configured to control thepassing of coolant into and out of the coolant channels.

FIG. 6 shows a transverse cross-section schematic of coaxial cableembodiments having coolant passages.

FIG. 7 shows a coolant circulating tube (e.g., coolant needle, catheter)positioned within an energy emission device having an outer conductorand a dielectric material.

FIG. 8 schematically shows the distal end of a device (e.g., antenna ofan ablation device) of the present invention that comprises a center feddipole component of the present invention.

FIG. 9 shows the test setup and position of temperature measurementstations. As shown, the ablation needle shaft for all experiments was20.5 cm. Probes 1, 2 and 3 were located 4, 8 and 12 cm proximal to thetip of the stainless needle.

FIG. 10 shows treatment at 35% (microwaves “on” from 13:40 to 13:50)with anomalously high (6.5%) reflected power. Probe 3 was initiallyplaced just outside of the liver tissue, in air.

FIG. 11 shows 10 minute treatment at 45% (microwaves on from 14:58 to15:08) with anomalously high (6.5%) reflected power. Peak temperature atStation 4 was 40.25° C.

FIG. 12 shows one a coaxial cable having a region of its outer conductorremoved to create space for coolant flow in one embodiment of thepresent invention.

FIG. 13 shows a schematic view of an import/export box, a transportsheath, and a procedure device pod.

FIG. 14 shows an energy delivery device having two pullwires connectedwith a pullwire anchor.

FIG. 15 shows an external perspective of an energy delivery devicehaving inflexible regions and a flexible region.

FIG. 16 shows an energy delivery device having a narrow coaxialtransmission line connected with a larger coaxial transmission linepositioned within an antenna, which is connected with an innerconductor.

FIG. 17 shows a cross section of an energy delivery device havinginflexible regions and a flexible region.

FIG. 18 shows a procedure device hub connected to a procedure tablestrap.

FIG. 19 shows a custom sterile drape with a fenestration and a cableinserted through the fenestration.

FIG. 20 shows an energy delivery system of the present invention havinga generator connected to a procedure device hub via a cable, where theprocedure device hub is secured to a procedure table.

FIG. 21 demonstrates cooling with an energy delivery device. Atemperature profile during ablation measured 7 cm proximal to the tip ofthe antenna showed that cooling with chilled water can remove heatingcaused by more than 120 W input power (upper). A ˜3 cm ablation createdwith the cooled antenna (125 W, 5 min) shows no “tail” along theantenna. The ceramic tube and faceted tip make percutaneous introductionpossible (lower).

FIG. 22 shows a simulated temperature distribution along an antennashaft with various passive cooling techniques. A combination of thermalresistors and insulating sheath reduced proximal temperatures mostsignificantly.

FIG. 23 shows microwave (left) and RF (right) ablations created in 10min in normal porcine lung shown at equal scale. Microwave ablationswere larger and more spherical than RF ablations.

FIG. 24 shows the experimental setup (top) and results for temperaturesmeasured along an antenna shaft while 35 W of heat are generated insidethe antenna shaft (bottom). Only 1.0 stp L/min CO₂ flow was required tokeep temperatures from rising more than 8° C. at any point along theshaft. 10 stp L/min was able to offset 50 W of heating power.

FIG. 25 shows the experimental setup (top) and results for temperaturesmeasured along the antenna shaft while the antenna tip is maintained at150° C. for 0, 13 and 23.8 stp L/min NC—CO₂ flow (bottom). Note thatheating was only considered for thermal conduction from the antennatip—no internal heating was considered in this test.

FIG. 26 shows that pulses of CO₂ as small as 1 stp L/min for 10 scounterbalance the thermally conductive heating from the tip of theantenna.

FIG. 27 shows conventional and HighlY-contstrained backPRojection (HYPR)image resolution as a function of time

FIG. 28 shows standard and HighlY-contstrained backPRojection (HYPR)tumor images over periods of time.

FIG. 29 shows an energy delivery device embodiment.

FIG. 30 shows an energy delivery device embodiment.

FIG. 31 shows an energy delivery device embodiment within a proceduresetting.

FIG. 32 shows a variety of exemplary configurations for using thedielectric material of coaxial transmission lines as coolant: a)conventional coaxial configuration; b) the dielectric space is dividedinto one coolant channel and one return channel; c) the dielectric spaceis divided into for chambers, one coolant channel, one return channel,and two non-flow channels; d) the dielectric space is divided into forchambers, two coolant channels and two return channels; e) one coolantchannel and one return channel within the dielectric space; f) twocoolant channels and two return channels within the dielectric space; g)four coolant channels and four return channels within the dielectricspace; h) porous dielectric material allows coolant to flow through thedielectric material; i) the dielectric space is divided into fourchambers, flow of coolant into the chambers expands the collapsiblechannels, increasing the cross-sectional profile of the channels; and j)a collapsible channel adopts a collapsed conformation, reducing itscross-sectional profile in the absence of coolant flow, coolant flowexpands the coolant channel, increasing the cross-sectional profile ofthe channel (“C” and “R” designate potential coolant (C) and return (R)channels.

FIG. 33 shows exemplary “wagon wheel” cross-sections of coaxialtransmission lines in which the dielectric material divides the spacebetween the inner and outer conductors in channels.

FIG. 34 shows an exemplary “wagon wheel” transmission line mounted withan outer sheath and cutting trocar; coolant flow through the coolanttube and channel is indicated.

DETAILED DESCRIPTION

The present invention relates to comprehensive systems, devices andmethods for delivering energy (e.g., microwave energy, radiofrequencyenergy) to tissue for a wide variety of applications, including medicalprocedures (e.g., tissue ablation (e.g. tumor ablation), resection,cautery, vascular thrombosis, intraluminal ablation of a hollow viscus,cardiac ablation for treatment of arrhythmias, electrosurgery, tissueharvest, cosmetic surgery, intraocular use, etc.). In some embodiments,the present invention provides systems for the delivery of microwaveenergy comprising a power supply, a means of directing, controlling anddelivering power (e.g., a power splitter), a processor, an energyemitting device, a cooling system, an imaging system, a temperaturemonitoring system, a device placement system, and/or a tracking system.In particular, systems, devices, and methods are provided for treating adifficult to access tissue region (e.g., a peripheral lung tumor)through use of the energy delivery systems of the present invention.

The systems of the present invention may be combined within varioussystem/kit embodiments. For example, the present invention providessystems comprising one or more of a generator, a power distributionsystem, a means of directing, controlling and delivering power (e.g., apower splitter), an energy applicator, device placement systems (e.g.multiple catheter system), along with any one or more accessorycomponent (e.g., surgical instruments, software for assisting inprocedure, processors, temperature monitoring devices, etc.). Thepresent invention is not limited to any particular accessory component.

The systems of the present invention may be used in any medicalprocedure (e.g., percutaneous or surgical) involving delivery of energy(e.g., radiofrequency energy, microwave energy, laser, focusedultrasound, etc.) to a tissue region. The systems are not limited totreating a particular type or kind of tissue region (e.g., brain, liver,heart, blood vessels, foot, lung, bone, etc.). For example, the systemsof the present invention find use in ablating tumor regions (e.g. lungtumors (e.g. peripheral lung tumors)). Additional treatments include,but are not limited to, treatment of heart arrhythmia, tumor ablation(benign and malignant), control of bleeding during surgery, aftertrauma, for any other control of bleeding, removal of soft tissue,tissue resection and harvest, treatment of varicose veins, intraluminaltissue ablation (e.g., to treat esophageal pathologies such as Barrett'sEsophagus and esophageal adenocarcinoma), treatment of bony tumors,normal bone, and benign bony conditions, intraocular uses, uses incosmetic surgery, treatment of pathologies of the central nervous systemincluding brain tumors and electrical disturbances, sterilizationprocedures (e.g., ablation of the fallopian tubes) and cauterization ofblood vessels or tissue for any purposes. In some embodiments, thesurgical application comprises ablation therapy (e.g., to achievecoagulative necrosis). In some embodiments, the surgical applicationcomprises tumor ablation to target, for example, primary or metastatictumors or peripheral lung nodules. In some embodiments, the surgicalapplication comprises the control of hemorrhage (e.g. electrocautery).In some embodiments, the surgical application comprises tissue cuttingor removal. In some embodiments, the device is configured for movementand positioning, with minimal damage to the tissue or organism, at anydesired location, including but not limited to, the brain, neck, chest,abdomen, pelvis, and extremities. In some embodiments, the device isconfigured for guided delivery, for example, by computerized tomography,ultrasound, magnetic resonance imaging, fluoroscopy, and the like.

In some embodiments, the present invention provides devices, systems,and methods for placing energy delivery devices in difficult to reachstructures, tissue regions, and/or organs (e.g. a branched structure(e.g. human lungs). The power generation and distribution systems; meansof directing, controlling and delivering power (e.g., a power splitter);energy applicators; and accessory components (e.g., surgicalinstruments, software for assisting in procedure, processors,temperature monitoring devices, etc.) described herein find use withsystems (e.g. multiple catheter systems (e.g. primary catheter, channelcatheter, and steerable navigation catheter)) for accurate placement ofenergy delivery devices in difficult to access tissue regions.

In some embodiments, the present invention provides devices, systems,and methods for reducing heat loss from devices delivering energy (e.g.microwave energy) to a tissue region of a subject, and/or to reduceundesired heating within and along an energy delivery device. In someembodiments, undesired heat loss form energy delivery devices and/orundesired heating within and along an energy delivery device compromisesthe efficiency of energy-delivery procedures, results in damage totissues surrounding the target site and/or along the delivery path, andrequires increased energy to achieve efficacious energy delivery at thetarget site. In some embodiments, reduces heating and/or heat lossthrough: insulator materials (e.g. porous insulators), coolant deliveryalong the energy delivery device, specialized cable configurations (e.g.one or more coolant channels, inflatable coolant channels, etc.),low-heat energy delivery programs (e.g. low energy, pulsed programs,etc.), and other suitable heat-loss-reduction and/ortemperature-reduction devices, systems, and methods find use with thepresent invention.

The illustrated embodiments provided below describe the systems of thepresent invention in terms of medical applications (e.g., ablation oftissue through delivery of microwave energy). However, it should beappreciated that the systems of the present invention are not limited tomedical applications. The systems may be used in any setting requiringdelivery of energy to a load (e.g., agricultural settings, manufacturesettings, research settings, etc.). The illustrated embodiments describethe systems of the present invention in terms of microwave energy. Itshould be appreciated that the systems of the present invention are notlimited to a particular type of energy (e.g., radiofrequency energy,microwave energy, focused ultrasound energy, laser, plasma).

The systems of the present invention are not limited to any particularcomponent or number of components. In some embodiments, the systems ofthe present invention include, but are not limited to including, a powersupply, a means of directing, controlling and delivering power (e.g., apower splitter), a processor, an energy delivery device with an antenna,a cooling system, an imaging system, a device placement system, and/or atracking system. When multiple antennas are in use, the system may beused to individually control each antenna separately.

FIG. 1 shows an exemplary system of the invention. As shown, the energydelivery system comprises a power supply, a transmission line, a powerdistribution component (e.g., power splitter), a processor, an imagingsystem, a temperature monitoring system and an energy delivery device.In some embodiments, as shown, the components of the energy deliverysystems are connected via a transmission line, cables, etc. In someembodiments, the energy delivery device is separated from the powersupply, a means of directing, controlling and delivering power (e.g., apower splitter), processor, imaging system, temperature monitoringsystem across a sterile field barrier.

Exemplary components of the energy delivery systems are described inmore detail in the following sections: I. Power Supply; II. Energydelivery devices; III. Processor; IV. Imaging Systems; V. TuningSystems; VI. Temperature Adjustment Systems; VII. IdentificationSystems; VIII. Temperature Monitoring Devices; IX. Procedure DeviceHubs; X. Uses, and XI. Device Placement Systems.

I. Power Supply

The energy utilized within the energy delivery systems of the presentinvention is supplied through a power supply. The present invention isnot limited to a particular type or kind of power supply. In someembodiments, the power supply is configured to provide energy to one ormore components of the energy delivery systems of the present invention(e.g., ablation devices). The power supply is not limited to providing aparticular type of energy (e.g., radiofrequency energy, microwaveenergy, radiation energy, laser, focused ultrasound, etc.). The powersupply is not limited to providing particular amounts of energy or at aparticular rate of delivery. In some embodiments, the power supply isconfigured to provide energy to an energy delivery device for purposesof tissue ablation.

The present invention is not limited to a particular type of powersupply. In some embodiments, the power supply is configured to provideany desired type of energy (e.g., microwave energy, radiofrequencyenergy, radiation, cryo energy, electroporation, high intensity focusedultrasound, and/or mixtures thereof). In some embodiments, the type ofenergy provided with the power supply is microwave energy. In someembodiments, the power supply provides microwave energy to ablationdevices for purposes of tissue ablation. The use of microwave energy inthe ablation of tissue has numerous advantages. For example, microwaveshave a broad field of power density (e.g., approximately 2 cmsurrounding an antenna depending on the wavelength of the appliedenergy) with a correspondingly large zone of active heating, therebyallowing uniform tissue ablation both within a targeted zone and inperivascular regions (see, e.g., International Publication No. WO2006/004585; herein incorporated by reference in its entirety). Inaddition, microwave energy has the ability to ablate large or multiplezones of tissue using multiple probes with more rapid tissue heating.Microwave energy has an ability to penetrate tissue to create deeplesions with less surface heating. Energy delivery times are shorterthan with radiofrequency energy and probes can heat tissue sufficientlyto create an even and symmetrical lesion of predictable and controllabledepth. Microwave energy is generally safe when used near vessels. Also,microwaves do not rely on electrical conduction as it radiates throughtissue, fluid/blood, as well as air. Therefore, microwave energy can beused in tissue, lumens, lungs, and intravascularly.

In some embodiments, the power supply is an energy generator. In someembodiments, the generator is configured to provide as much as 100 wattsof microwave power of a frequency of from 915 MHz to 5.8 GHz, althoughthe present invention is not so limited. In some embodiments, aconventional magnetron of the type commonly used in microwave ovens ischosen as the generator. In some embodiments, a single-magnetron basedgenerator (e.g., with an ability to output 300 W through a singlechannel, or split into multiple channels) is utilized. It should beappreciated, however, that any other suitable microwave power source cansubstituted in its place. In some embodiments, the types of generatorsinclude, but are not limited to, those available from Cober-Muegge, LLC,Norwalk, Conn., USA, Sairem generators, and Gerling Applied Engineeringgenerators. In some embodiments, the generator has at leastapproximately 60 Watts available (e.g., 50, 55, 56, 57, 58, 59, 60, 61,62, 65, 70, 100, 500, 1000 Watts). For a higher-power operation, thegenerator is able to provide approximately 300 Watts (e.g., 200 Watts,280, 290, 300, 310, 320, 350, 400, 750 Watts). In some embodiments,wherein multiple antennas are used, the generator is able to provide asmuch energy as necessary (e.g., 400 Watts, 500, 750, 1000, 2000, 10,000Watts). In some embodiments, the generator comprises solid stateamplifier modules which can be operated separately and phase-controlled.In some embodiments, generator outputs are combined constructively toincrease total output power. In some embodiments, the power supplydistributes energy (e.g., collected from a generator) with a powerdistribution system. The present invention is not limited to aparticular power distribution system. In some embodiments, the powerdistribution system is configured to provide energy to an energydelivery device (e.g., a tissue ablation catheter) for purposes oftissue ablation. The power distribution system is not limited to aparticular manner of collecting energy from, for example, a generator.The power distribution system is not limited to a particular manner ofproviding energy to ablation devices. In some embodiments, the powerdistribution system is configured to transform the characteristicimpedance of the generator such that it matches the characteristicimpedance of an energy delivery device (e.g., a tissue ablationcatheter).

In some embodiments, the power distribution system is configured with avariable power splitter so as to provide varying energy levels todifferent regions of an energy delivery device or to different energydelivery devices (e.g., a tissue ablation catheter). In someembodiments, the power splitter is provided as a separate component ofthe system. In some embodiments, the power splitter is used to feedmultiple energy delivery devices with separate energy signals. In someembodiments, the power splitter electrically isolates the energydelivered to each energy delivery device so that, for example, if one ofthe devices experiences an increased load as a result of increasedtemperature deflection, the energy delivered to that unit is altered(e.g., reduced, stopped) while the energy delivered to alternate devicesis unchanged. The present invention is not limited to a particular typeor kind of power splitter. In some embodiments, the power splitter isdesigned by SM Electronics. In some embodiments, the power splitter isconfigured to receive energy from a power generator and provide energyto additional system components (e.g., energy delivery devices). In someembodiments the power splitter is able to connect with one or moreadditional system components (e.g., 1, 2, 3, 4, 5, 7, 10, 15, 20, 25,50, 100, 500 . . . ). In some embodiments, the power splitter isconfigured to deliver variable amounts of energy to different regionswithin an energy delivery device for purposes of delivering variableamounts of energy from different regions of the device. In someembodiments, the power splitter is used to provide variable amounts ofenergy to multiple energy delivery devices for purposes of treating atissue region. In some embodiments, the power splitter is configured tooperate within a system comprising a processor, an energy deliverydevice, a temperature adjustment system, a power splitter, a tuningsystem, and/or an imaging system. In some embodiments, the powersplitter is able to handle maximum generator outputs plus, for example,25% (e.g., 20%, 30%, 50%). In some embodiments, the power splitter is a1000-watt-rated 2-4 channel power splitter.

In some embodiments, where multiple antennas are employed, the system ofthe present invention may be configured to run them simultaneously orsequentially (e.g., with switching). In some embodiments, the system isconfigured to phase the fields for constructive or destructiveinterference. Phasing may also be applied to different elements within asingle antenna. In some embodiments, switching is combined with phasingsuch that multiple antennas are simultaneously active, phase controlled,and then switched to a new set of antennas (e.g., switching does notneed to be fully sequential). In some embodiments, phase control isachieved precisely. In some embodiments, phase is adjusted continuouslyso as to move the areas of constructive or destructive interference inspace and time. In some embodiments, the phase is adjusted randomly. Insome embodiments, random phase adjustment is performed by mechanicaland/or magnetic interference.

II. Energy Delivery Devices

The energy delivery systems of the present invention contemplate the useof any type of device configured to deliver (e.g., emit) energy (e.g.,ablation device, surgical device, etc.) (see, e.g., U.S. Pat. Nos.7,101,369, 7,033,352, 6,893,436, 6,878,147, 6,823,218, 6,817,999,6,635,055, 6,471,696, 6,383,182, 6,312,427, 6,287,302, 6,277,113,6,251,128, 6,245,062, 6,026,331, 6,016,811, 5,810,803, 5,800,494,5,788,692, 5,405,346, 4,494,539, U.S. patent application Ser. Nos.11/728,460, 11/728,457, 11/728,428, 11/237,136, 11/236,985, 10/980,699,10/961,994, 10/961,761, 10/834,802, 10/370,179, 09/847,181; GreatBritain Patent Application Nos. 2,406,521, 2,388,039; European PatentNo. 1395190; and International Patent Application Nos. WO 06/008481, WO06/002943, WO 05/034783, WO 04/112628, WO 04/033039, WO 04/026122, WO03/088858, WO 03/039385 WO 95/04385; each herein incorporated byreference in their entireties). Such devices include any and allmedical, veterinary, and research applications devices configured forenergy emission, as well as devices used in agricultural settings,manufacturing settings, mechanical settings, or any other applicationwhere energy is to be delivered.

In some embodiments, the systems utilize energy delivery devices havingtherein antennae configured to emit energy (e.g., microwave energy,radiofrequency energy, radiation energy). The systems are not limited toparticular types or designs of antennae (e.g., ablation device, surgicaldevice, etc.). In some embodiments, the systems utilize energy deliverydevices having linearly shaped antennae (see, e.g., U.S. Pat. Nos.6,878,147, 4,494,539, U.S. patent application Ser. Nos. 11/728,460,11/728,457, 11/728,428, 10/961,994, 10/961,761; and International PatentApplication No., WO 03/039385; each herein incorporated by reference intheir entireties). In some embodiments, the systems utilize energydelivery devices having non-linearly shaped antennae (see, e.g., U.S.Pat. Nos. 6,251,128, 6,016,811, and 5,800,494, U.S. patent applicationSer. No. 09/847,181, and International Patent Application No. WO03/088858; each herein incorporated by reference in their entireties).In some embodiments, the antennae have horn reflection components (see,e.g., U.S. Pat. Nos. 6,527,768, 6,287,302; each herein incorporated byreference in their entireties). In some embodiments, the antenna has adirectional reflection shield (see, e.g., U.S. Pat. No. 6,312,427;herein incorporated by reference in its entirety). In some embodiments,the antenna has therein a securing component so as to secure the energydelivery device within a particular tissue region (see, e.g., U.S. Pat.Nos. 6,364,876, and 5,741,249; each herein incorporated by reference intheir entireties).

In some embodiments, antennae configured to emit energy comprise coaxialtransmission lines. The devices are not limited to particularconfigurations of coaxial transmission lines. Examples of coaxialtransmission lines include, but are not limited to, coaxial transmissionlines developed by Pasternack, Micro-coax, and SRC Cables. In someembodiments, the coaxial transmission line has a center conductor, adielectric element, and an outer conductor (e.g., outer shield). In someembodiments, the systems utilize antennae having flexible coaxialtransmission lines (e.g., for purposes of positioning around, forexample, pulmonary veins or through tubular structures) (see, e.g., U.S.Pat. Nos. 7,033,352, 6,893,436, 6,817,999, 6,251,128, 5,810,803,5,800,494; each herein incorporated by reference in their entireties).In some embodiments, the systems utilize antennae having rigid coaxialtransmission lines (see, e.g., U.S. Pat. No. 6,878,147, U.S. patentapplication Ser. Nos. 10/961,994, 10/961,761, and International PatentApplication No. WO 03/039385; each herein incorporated by reference intheir entireties).

In some embodiments, the energy delivery devices have a coaxialtransmission line positioned within the antenna, and a coaxialtransmission line connecting with the antenna. In some embodiments, thesize of the coaxial transmission line within the antenna is larger thanthe coaxial transmission line connected with the antenna. The coaxialtransmission line within the antenna and the coaxial transmission lineconnecting with the antenna are not limited to particular sizes. Forexample, in some embodiments, whereas the coaxial transmission lineconnected with the antenna is approximately 0.032 inches, the size ofthe coaxial transmission line within the antenna is larger than 0.032inches (e.g., 0.05 inches, 0.075 inches, 0.1 inches, 0.5 inches). Insome embodiments, the coaxial transmission line within the antenna hasan inner conductor that is stiff and thick. In some embodiments, the endof the coaxial transmission line within the antenna is sharpened forpercutaneous use. In some embodiments, the dielectric coating of thecoaxial transmission line within the antenna is PTFE (e.g., for purposesof smoothing transitions from a cannula to an inner conductor (e.g., athin and sharp inner conductor)). FIG. 16 shows an energy deliverydevice 1600 having a narrow coaxial transmission line 1610 connectedwith a larger coaxial transmission line 1620 positioned within anantenna 1630, which is connected with an inner conductor 1640.

The present invention is not limited to a particular coaxialtransmission line shape. Indeed, in some embodiments, the shape of thecoaxial transmission line and/or the dielectric element is selectedand/or adjustable to fit a particular need. FIG. 2 shows some of thevarious, non-limiting shapes the coaxial transmission line and/or thedielectric element may assume.

In some embodiments, the outer conductor is a 20-gauge needle or acomponent of similar diameter to a 20-gauge needle. Preferably, forpercutaneous use, the outer conductor is not larger than a 17-gaugeneedle (e.g., no larger than a 16-gauge needle). In some embodiments,the outer conductor is a 17-gauge needle. However, in some embodiments,larger devices are used, as desired. For example, in some embodiments, a12-gauge diameter is used. The present invention is not limited by thesize of the outer conductor. In some embodiments, the outer conductor isconfigured to fit within series of larger needles for purposes ofassisting in medical procedures (e.g., assisting in tissue biopsy) (see,e.g., U.S. Pat. Nos. 6,652,520, 6,582,486, 6,355,033, 6,306,132; eachherein incorporated by reference in their entireties). In someembodiments, the center conductor is configured to extend beyond theouter conductor for purposes of delivering energy to a desired location.In some embodiments, some or all of the feedline characteristicimpedance is optimized for minimum power dissipation, irrespective ofthe type of antenna that terminates at its distal end.

In some embodiments, the energy delivery devices have a triaxialtransmission line. In some embodiments, the present invention provides atriaxial microwave probe design where the outer conductor allowsimproved tuning of the antenna to reduce reflected energy through thetransmission line. This improved tuning reduces heating of thetransmission line allowing more power to be applied to the tissue and/ora smaller transmission line (e.g. narrower) to be used. Further, theouter conductor may slide with respect to the inner conductors to permitadjustment of the tuning to correct for effects of the tissue on thetuning. In some embodiments, and outer conductor is stationary withrespect to the inner conductors. In some embodiments, the presentinvention provides a probe having a first conductor and a tubular secondconductor coaxially around the first conductor but insulated therefrom(e.g. insulated by a dielectric material and/or coolant). A tubularthird conductor is fit coaxially around the first and second conductors.The first conductor may extend beyond the second conductor into tissuewhen a proximal end of the probe is inserted into a body. The secondconductor may extend beyond the third conductor into the tissue toprovide improved tuning of the probe limiting power dissipated in theprobe outside of the exposed portions of the first and secondconductors. The third tubular conductor may be a channel catheter forinsertion into the body or may be separate from a channel catheter. Insome embodiments, a device comprising first, second, and thirdconductors is sufficiently flexible to navigate a winding path (e.g.through a branched structure within a subject (e.g. through the brachialtree)). In some embodiments, the first and second conductors may fitslidably within the third conductor. In some embodiments, the presentinvention provides a probe that facilitates tuning of the probe intissue by sliding the first and second conductors inside of the thirdconductor. In some embodiments, the probe includes a lock attached tothe third conductor to adjustably lock a sliding location of the firstand second conductors with respect to the third conductor. In someembodiments, the present invention provides a triaxial transmissionline, as described in U.S. Pat. No. 7,101,369, U.S. Pat. App. No.2007/0016180, U.S. Pat. App. No. 2008/0033424, U.S. Pat. App. No.20100045558, U.S. Pat. App. No. 20100045559, herein incorporated byreference in their entireties.

In some embodiments, one or more components of a coaxial transmissionline or triaxial transmission line comprise a flexible and/orcollapsible material (e.g. biaxially-oriented polyethylene terephthalate(boPET) (e.g. MYLAR, MELINEX, HOSTAPHAN, etc.), etc.). In someembodiments, the outer conductor of the coaxial transmission line (orsecond (middle) conductor of a triaxial transmission line) comprises aflexible and/or collapsible material (e.g. boPET). In some embodiments,a component of a coaxial transmission line (e.g. outer conductor)comprises boPET coated in one or more films to provide desiredcharacteristics (e.g. electric conductivity, heat insulation, etc.). Insome embodiments, a collapsible outer conductor allows the transmissionline to adopt variable cross-sectional profile (e.g. variable diameter,variable shape, etc.) (SEE, e.g., FIGS. 32I and 32J). In someembodiments, a collapsible outer conductor encircles the innerconductor. In some embodiments, a collapsible outer conductor forms aclosed sack around the inner conductor. In some embodiments, fluid (e.g.dielectric material, and/or coolant) can be flowed through thecollapsible outer conductor to adjust its variable cross-sectionalprofile. In some embodiments, a collapsible outer conductor adopts acollapsed conformation when fluid is withdrawn from the area within theouter conductor, thereby decreasing the pressure within the outerconductor. In some embodiments, in a collapsed conformation the outerconductor displays a minimized cross-sectional profile (SEE, e.g., FIGS.32I and 32J). In some embodiments, in a collapsed conformation the outerconductor closely hugs the periphery of the inner conductor (SEE 32J).In some embodiments, the collapsed conformation provides decreasedcross-sectional profile and/or increased flexibility to aid ininsertion, placement, and/or withdrawal of the coaxial transmissionline. In some embodiments, a collapsible outer conductor adopts anexpanded conformation when fluid is flowed into the area within theouter conductor, thereby increasing the pressure within the outerconductor. In some embodiments, in an expanded conformation the outerconductor displays a maximized cross-sectional profile. In someembodiments, in an expanded conformation the distance between the innerconductor and the outer conductor is maximized. In some embodiments, theexpanded conformation provides increased cross-sectional profile and/oroptimized conduction to aid in energy delivery along the coaxialtransmission line. In some embodiments, the expanded conformationprovides an increased volume of coolant along the coaxial transmissionline. In some embodiments, the collapsible outer conductor adopts anysuitable shape in the expanded conformation. In some embodiments, thecoaxial transmission line runs through a lumen, the shape of whichdictates the expanded shape of the collapsible outer conductor. In someembodiments, the collapsible outer conductor adopts any suitable shapein the collapsed conformation. In some embodiments, the shape orconfiguration of the dielectric material dictates the collapsed shape ofthe collapsible outer conductor. In some embodiments, a collapsibleouter conductor also comprises a coolant sheath, as described herein.

In some embodiments, the dielectric material is shaped to provide toprovide channels within the dielectric space (e.g. air channels, coolantchannels, vacant channels, etc.) (SEE FIG. 33). In some embodiments,channels are completely or partially encompassed by the dielectricmaterial. In some embodiments, the dielectric material divides thedielectric space into channels to create a “wagon wheel” conformation(SEE FIGS. 33 and 34). In some embodiments, the dielectric materialdivides the dielectric space (e.g. the space between the inner and outerconductors) into 1 or more channels (e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,or more channels). In some embodiments, the channels within thedielectric space serve as coolant channels. In some embodiments, thechannels within the dielectric space house coolant tubes. In someembodiments, a coolant tube within a channel delivers coolant along thetransmission line, and a coolant channel provides the return path, tothe proximal end of the transmission line (SEE, e.g., FIG. 34). In someembodiments, a channel comprises multiple coolant tubes (e.g. coolantand return). In some embodiment, channels formed by the dielectricmaterial comprise a non-metallic filler. In some embodiments,non-metallic filler resides in the channels in the distal region of thetransmission line (e.g. beyond the end of the outer conductor).

In some embodiments, the energy delivery devices are provided with aproximal portion and a distal portion, wherein the distal portion isdetachable and provided in a variety of different configurations thatcan attach to a core proximal portion. For example, in some embodiments,the proximal portion comprises a handle and an interface to othercomponents of the system (e.g., power supply) and the distal portioncomprises a detachable antenna having desired properties. A plurality ofdifferent antenna configured for different uses may be provided andattached to the handle unit for the appropriate indication.

In some embodiments, multiple (e.g., more than 1) (e.g., 2, 3, 4, 5, 10,20, etc.) coaxial transmission lines and/or triaxial transmission linesare positioned within each energy delivery device for purposes ofdelivery high amounts of energy over an extended period of time. Inexperiments conducted during the course of developing embodiments forthe present invention, it was determined that an energy delivery devicehaving three lower power coaxial transmission lines (e.g., positionedwithin the same probe) (e.g., within a 13 gauge needle) was able todeliver higher amounts of energy for a longer period of time than anenergy delivery device having a higher power coaxial transmission line.

In some embodiments, the device is configured to attach with adetachable handle. The present invention is not limited to a particulartype of detachable handle. In some embodiments, the detachable handle isconfigured to connect with multiple devices (e.g., 1, 2, 3, 4, 5, 10,20, 50 . . . ) for purposes of controlling the energy delivery throughsuch devices. In some embodiments, the handle is designed with a poweramplifier for providing power to an energy delivery device.

In some embodiments, the device is designed to physically surround aparticular tissue region for purposes of energy delivery (e.g., thedevice may be flexibly shaped around a particular tissue region). Forexample, in some embodiments, the device may be flexibly shaped around ablood vessel (e.g., pulmonary vein) for purposes of delivering energy toa precise region within the tissue.

In some embodiments, the energy delivery devices are configured forshape retention upon exposure to a compressive force. The energydelivery devices are not limited to a particular configuration forretaining shape upon exposure to a compressive force. In someembodiments, the energy delivery devices have therein a pullwire systemfor purposes of shape retention upon compression. The present inventionis not limited to a particular type of pullwire system. In someembodiments, the pullwire system comprises one or more pullwires (e.g.,1 pullwire, 2 pullwires, 5 pullwires, 10 pullwires, 50 pullwires)connected with a pullwire anchor. In some embodiments, contraction(e.g., pushing, pulling) of the one or more pullwires connected to thepullwire anchor (e.g., contraction by a user) results in the assumptionof an inflexible state by the energy delivery device such that uponexposure to a compressive force the energy delivery device retains itsshape. In some embodiments, the pullwires can be locked in a contractedposition. In some embodiments, the energy delivery devices having one ormore pullwires connected with a pullwire anchor retains flexibility inthe absence pullwire contraction. FIG. 14 shows an energy deliverydevice 1400 having two pullwires 1410, 1420 connected with a pullwireanchor 1430. In some embodiments, the energy delivery devices have threeor more pullwires arranged in a symmetrical pattern which arepre-stressed thereby providing a constant inflexible shape. In someembodiments, the pullwires are configured to automatically contract inresponse to a stimulation (e.g., an electrical stimulation, acompressive stimulation) (e.g., muscle wires). In some embodiments, thepullwires are configured to provide a balancing force in response to acompressive force (e.g., a counteracting force). In some embodiments,the pullwires are designed to bend at particular temperatures (e.g.,super elastic nitinol wires). In some embodiments, the bending ofpullwires at particular temperatures is a detectable event that can beused to monitor the status of a procedure.

In some embodiments, the energy delivery devices are configured to haveboth flexible and inflexible regions. The energy delivery devices arenot limited to particular configurations for having both flexible andinflexible regions. In some embodiments, the flexible regions compriseplastic (e.g., PEEK). In some embodiments, the inflexible regionscomprise ceramic. The flexible and inflexible regions are not limited toparticular positions within the energy delivery devices. In someembodiments, the flexible region is positioned in a region experiencinglower amounts of microwave field emission. In some embodiments, theinflexible region is positioned in a region experiencing high amounts ofmicrowave field emission (e.g., located over the proximal portion of theantenna to provide dielectric strength and mechanical rigidity). FIG. 15shows an external perspective of an energy delivery device 1500 havinginflexible regions 1510 and 1520 (e.g., ceramic), and a flexible region1530 (e.g., PEEK). FIG. 17 shows a cross section of an energy deliverydevice 1700 having inflexible regions 1710 and 1720, and a flexibleregion 1730. As shown, the inflexible regions 1710 and 1720 aregradually tapered so as to, for example, provide a larger surface areafor bonding with the cannula, and so as to, for example, distributestresses from bending forces over a larger surface area. As shown, theflexible region 1730 is positioned on the outside of the joint forpurposes of improving strength due to its large diameter size. In someembodiments, the gradual taper of the inflexible regions are filled witha bonding material to provide additional strength. In some embodiments,the energy delivery devices have a heat shrink over the distal portion(e.g., the antenna) for providing additional durability.

In some embodiments, the material of the antenna is durable and providesa high dielectric constant. In some embodiments, the material of theantenna is zirconium and/or a functional equivalent of zirconium. Insome embodiments, the energy delivery device is provided as two or moreseparate antenna attached to the same or different power supplies. Insome embodiments, the different antennas are attached to the samehandle, while in other embodiments different handles are provided foreach antenna. In some embodiments, multiple antennae are used within apatient simultaneously or in series (e.g., switching) to deliver energyof a desired intensity and geometry within the patient. In someembodiments, the antennas are individually controllable. In someembodiments, the multiple antennas may be operated by a single user, bya computer, or by multiple users.

In some embodiments, the energy delivery devices are designed to operatewithin a sterile field. The present invention is not limited to aparticular sterile field setting. In some embodiments, the sterile fieldincludes a region surrounding a subject (e.g., an operating table). Insome embodiments, the sterile field includes any region permittingaccess only to sterilized items (e.g., sterilized devices, sterilizedaccessory agents, sterilized body parts). In some embodiments, thesterile field includes any region vulnerable to pathogen infection. Insome embodiments, the sterile field has therein a sterile field barrierestablishing a barrier between a sterile field and a non-sterile field.The present invention is not limited to a particular sterile fieldbarrier. In some embodiments, the sterile field barrier is the drapessurrounding a subject undergoing a procedure involving the systems ofthe present invention (e.g., tissue ablation). In some embodiments, aroom is sterile and provides the sterile field. In some embodiments, thesterile field barrier is established by a user of the systems of thepresent invention (e.g., a physician). In some embodiments, the sterilefield barrier hinders entry of non-sterile items into the sterile field.In some embodiments, the energy delivery device is provided in thesterile field, while one or more other components of the system (e.g.,the power supply) are not contained in the sterile field.

In some embodiments, the energy delivery devices have therein protectionsensors designed to prevent undesired use of the energy deliverydevices. The energy delivery devices are not limited to a particulartype or kind of protection sensors. In some embodiments, the energydelivery devices have therein a temperature sensor designed to measurethe temperature of, for example, the energy delivery device and/or thetissue contacting the energy delivery device. In some embodiments, as atemperature reaches a certain level the sensor communicates a warning toa user via, for example, the processor. In some embodiments, the energydelivery devices have therein a skin contact sensor designed to detectcontact of the energy delivery device with skin (e.g., an exteriorsurface of the skin). In some embodiments, upon contact with undesiredskin, the skin contact sensor communicates a warning to a user via, forexample, the processor. In some embodiments, the energy delivery deviceshave therein an air contact sensor designed to detect contact of theenergy delivery device with ambient air (e.g., detection throughmeasurement of reflective power of electricity passing through thedevice). In some embodiments, upon contact with undesired air, the skincontact sensor communicates a warning to a user via, for example, theprocessor. In some embodiments, the sensors are designed to prevent useof the energy delivery device (e.g., by automatically reducing orpreventing power delivery) upon detection of an undesired occurrence(e.g., contact with skin, contact with air, undesired temperatureincrease/decrease). In some embodiments, the sensors communicate withthe processor such that the processor displays a notification (e.g., agreen light) in the absence of an undesired occurrence. In someembodiments, the sensors communicate with the processor such that theprocessor displays a notification (e.g., a red light) in the presence ofan undesired occurrence and identifies the undesired occurrence.

In some embodiments, the energy delivery devices are used above amanufacturer's recommended power rating. In some embodiments, coolingtechniques described herein are applied to permit higher power delivery.The present invention is not limited to a particular amount of powerincrease. In some embodiments, power ratings exceed manufacturer'srecommendation by 5× or more (e.g., 5×, 6×, 10×, 15×, 20×, etc.).

In addition, the devices of the present invention are configured todeliver energy from different regions of the device (e.g., outerconductor segment gaps, described in more detail below) at differenttimes (e.g., controlled by a user) and at different energy intensities(e.g., controlled by a user). Such control over the device permits thephasing of energy delivery fields for purposes of achieving constructivephase interference at a particular tissue region or destructive phaseinterference at a particular tissue region. For example, a user mayemploy energy delivery through two (or more) closely positioned outerconductor segments so as to achieve a combined energy intensity (e.g.,constructive phase interference). Such a combined energy intensity maybe useful in particularly deep or dense tissue regions. In addition,such a combined energy intensity may be achieved through utilization oftwo (or more) devices. In some embodiments, phase interference (e.g.,constructive phase interference, destructive phase interference),between one or more devices, is controlled by a processor, a tuningelement, a user, and/or a power splitter. Thus, the user is able tocontrol the release of energy through different regions of the deviceand control the amount of energy delivered through each region of thedevice for purposes of precisely sculpting an ablation zone.

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices with optimized characteristicimpedance, triaxial design, energy delivery devices having coolingpassage channels, “wagon wheel” cross-section, coolant fluid whichserves as dielectric material, porous dielectric material, energydelivery devices with a center fed dipole, and/or energy deliverydevices having a linear array of antennae components (each described inmore detail above and below).

The present invention provides a wide variety of methods for cooling thedevices. Some embodiments employ meltable barriers that, upon melting,permit the contact of chemicals that carry out an endothermic reaction.An example of such an embodiment is shown in FIG. 3. FIGS. 3A and 3Bdisplay a region of a coaxial transmission line (e.g., a channel) havingpartitioned segments with first and second materials blocked by meltablewalls for purposes of preventing undesired device heating (e.g., heatingalong the outer conductor). FIGS. 3A and 3B depict a standard coaxialtransmission line 300 configured for use within any of the energydelivery devices of the present invention. As shown in FIG. 3A, thecoaxial transmission line 300 has a center conductor 310, a dielectricmaterial 320, and an outer conductor 330. In addition, the coaxialtransmission line 300 has therein four partitioned segments 340segregated by walls 350 (e.g., meltable wax walls). The partitionedsegments 340 are divided into first partitioned segments 360 and secondpartitioned segments 370. In some embodiments, as shown in FIG. 3A, thefirst partitioned segments 360 and second partitioned segments 370 aresuccessively staggered. As shown in FIG. 3A, the first partitionedsegments 360 contain a first material (shading type one) and the secondpartitioned segments 370 contain a second material (shading type two).The walls 350 prevent the first material and second material frommixing. FIG. 3B shows the coaxial transmission line 300 described inFIG. 3A following an event (e.g., a temperature increase at one of thepartitioned segments 340). As shown, one of the walls 350 has meltedthereby permitting mixing of the first material contained in a region360 and second material contained in a region 370. FIG. 3B further showsnon-melted walls 350 where the temperature increase did not rise above acertain temperature threshold.

FIG. 4 shows an alternative embodiment. FIGS. 4A and 4B display acoaxial transmission line embodiment having partitioned segmentssegregated by meltable walls containing first and second materials(e.g., materials configured to generate a temperature reducing chemicalreaction upon mixing) preventing undesired device heating (e.g., heatingalong the outer conductor). FIGS. 4A and 4B show a coaxial transmissionline 400 configured for use within any of the energy delivery devices ofthe present invention. As shown in FIG. 4A, the coaxial transmissionline 400 has a center conductor 410, a dielectric material 420, and anouter conductor 430. In addition, the coaxial transmission line 400 hastherein four partitioned segments 440 segregated by walls 450. The walls450 each contain a first material 460 separated from a second material470. FIG. 4B shows the coaxial transmission line 400 described in FIG.4A following an event (e.g., a temperature increase at one of thepartitioned segments 440). As shown, one of the walls 450 has meltedthereby permitting mixing of the first material 460 and second material470 within the adjacent partitioned segments 440. FIG. 4B furtherdemonstrates non-melted walls 450 where the temperature increase did notrise above a certain temperature threshold.

In some embodiments, the device further comprises an anchoring elementfor securing the antenna at a particular tissue region. The device isnot limited to a particular type of anchoring element. In someembodiments, the anchoring element is an inflatable balloon (e.g.,wherein inflation of the balloon secures the antenna at a particulartissue region). An additional advantage of utilizing an inflatableballoon as an anchoring element is the inhibition of blood flow or airflow to a particular region upon inflation of the balloon. Such air orblood flow inhibition is particularly useful in, for example, cardiacablation procedures and ablation procedures involving lung tissue,vascular tissue, and gastrointestinal tissue. In some embodiments, theanchoring element is an extension of the antenna designed to engage(e.g., latch onto) a particular tissue region. Further examples include,but are not limited to, the anchoring elements described in U.S. Pat.Nos. 6,364,876, and 5,741,249; each herein incorporated by reference intheir entireties. In some embodiments, the anchoring element has acirculating agent (e.g. a gas delivered at or near its critical point;CO₂) that freezes the interface between antenna and tissue therebysticking the antenna in place. In such embodiments, as the tissue meltsthe antenna remains secured to the tissue region due to tissuedesiccation.

In some embodiments, the devices of the present invention are used inthe ablation of a tissue region having high amounts of air and/or bloodflow (e.g., pulmonary tissue, cardiac tissue, gastrointestinal tissue,vascular tissue). In some embodiments involving ablation of tissueregions having high amounts of air and/or blood flow, an element isfurther utilized for inhibiting the air and/or blood flow to that tissueregion. The present invention is not limited to a particular air and/orblood flow inhibition element. In some embodiments, the device iscombined with an endotracheal/endobronchial tube. In some embodiments, aballoon attached with the device may be inflated at the tissue regionfor purposes of securing the device(s) within the desired tissue region,and inhibiting blood and/or air flow to the desired tissue region.

Thus, in some embodiments, the systems, devices, and methods of thepresent invention provide an ablation device coupled with a componentthat provides occlusion of a passageway (e.g., bronchial occlusion). Theocclusion component (e.g., inflatable balloon) may be directly mountedon the ablation system or may be used in combination with anothercomponent (e.g., an endotracheal or endobronchial tube) associated withthe system.

In some embodiments, the devices of the present invention may be mountedonto additional medical procedure devices. For example, the devices maybe mounted onto endoscopes, intravascular catheters, bronchoscopes, orlaproscopes. In some embodiments, the devices are mounted onto steerablecatheters. In some embodiments, a flexible catheter is mounted on anendoscope, intravascular catheter or laparoscope. For example, theflexible catheter, in some embodiments, has multiple joints (e.g., likea centipede) that permits bending and steering as desired to navigate tothe desired location for treatment. In some embodiments, devices of thepresent invention are deployed through endoscopes, intravascularcatheters, bronchoscopes, or laproscopes.

In some embodiments, the energy delivery devices have therein a plugregion designed to separate interior portion of the energy deliverydevice so as to, for example, prevent cooling or heating of a portion orportions of the device while permitting cooling or heating of otherportions. The plug region may be configured to segregate any desiredregion or regions of an energy delivery device from any other. In someembodiments, the plug region is designed to prevent cooling of one ormore regions of an energy delivery device. In some embodiments, the plugregion is designed to prevent cooling of the portion of the energydelivery device configured to deliver ablative energy. The plug regionis not limited to a particular manner of preventing cooling of a portionof the device. In some embodiments, the plug region is designed to be incontact with a region having a reduced temperature (e.g., a region ofthe energy delivery device having circulated coolant). In someembodiments, the material of the plug region is such that it is able tobe in contact with a material or region having a low temperature withouthaving its temperature significantly reduced (e.g., an insulatingmaterial). The plug region is not limited to a particular type ofinsulating material (e.g., a synthetic polymer (e.g., polystyrene,polyicynene, polyurethane, polyisocyanurate), aerogel, fibre-glass,cork). The plug region is not limited to particular size dimensions. Insome embodiments, the size of the plug region is such that it is able toprevent the cooling effect of a circulating coolant from reducing thetemperature of other regions of the energy delivery device. In someembodiments, the plug region is positioned along the entire cannulaportion of an energy delivery device. In some embodiments, the plugregion is positioned at a distal portion of the cannula portion of anenergy delivery device. In some embodiments, the plug region wrapsaround the external portion of the cannula portion of an energy deliverydevice.

In some embodiments, the energy delivery devices have therein a “stick”region designed for securing the energy delivery device to a tissueregion. The stick region is not limited to a particular manner offacilitating association of an energy delivery device to a tissueregion. In some embodiments, the stick region is configured to attainand maintain a reduced temperature such that upon contact with a tissueregion, the tissue region adheres to the stick region thereby resultingin attachment of the energy delivery device with the tissue region. Thestick region is not limited to a particular material composition. Insome embodiments, the stick region is, for example, a metal material, aceramic material, a plastic material, and/or any combination of suchsubstances. In some embodiments, the stick region comprises any kind ofmaterial able to attain and maintain a temperature such that uponcontact with a tissue region induces adherence of the tissue region ontothe stick region. The stick region is not limited to particular sizedimensions. In some embodiments, the size of the stick region is suchthat it is able to maintain adherence of a tissue region duringsimultaneous tissue ablation and/or simultaneous movement (e.g.,positioning) of the energy delivery device. In some embodiments, two ormore stick regions are provided.

FIG. 29 shows an energy delivery device embodiment of the presentinvention. As shown, an energy delivery device 100 is positioned in thevicinity of an ablation zone 105. As shown, the energy delivery device100 has a cooling tube 110 and cable assembly 120 connected with ahandle 130, which is connected with a cooled probe cannula 140 connectedwith an antenna region 150. As shown, the region between the cooledprobe cannula 140 and the antenna region 150 has therein a stick region160 and a plug region 170. The stick region 160 is designed to attainand maintain a temperature accommodating adherence of a tissue regiononto its surface. The plug region 170 is designed to prevent a reductionin temperature resulting from the cooled probe cannula 140 and the stickregion 160 from affecting (e.g., reducing) the temperature within theantenna region 150. As shown, in these embodiments, the ablation zone105, encompasses both a cooled region of the energy delivery device 100(e.g., the cooled probe cannula 140 and the stick region 160) and anon-cooled region of the energy delivery device 100 (e.g., the plugregion 170 and the antenna region 150).

In some embodiments, the energy delivery systems of the presentinvention utilize devices configured for delivery of microwave energywith an optimized characteristic impedance (see, e.g., U.S. patentapplication Ser. No. 11/728,428; herein incorporated by reference in itsentirety). Such devices are configured to operate with a characteristicimpedance higher than 50Ω (e.g., between 50 and 90Ω; e.g., higher than50, . . . , 55, 56, 57, 58, 59, 60, 61, 62, . . . 90Ω, preferably at77Ω). In some embodiments, optimized characteristic impedance isachieved through selection of (or absence of) an appropriate dielectricmaterial. Energy delivery devices configured to operate with optimizedcharacteristic impedance are particularly useful in terms of tissueablation procedures, and provide numerous advantages over non-optimizeddevices. For example, a major drawback with currently available medicaldevices that utilize microwave energy is the undesired dissipation ofthe energy through transmission lines onto a subject's tissue resultingin undesired burning. Such microwave energy loss results fromlimitations within the design of currently available medical devices.Standard impedance for coaxial transmission lines within medical devicesis 50Ω or lower. Generally, coaxial transmission lines with impedancelower than 50Ω have high amounts of heat loss due to the presence ofdielectric materials with finite conductivity values. As such, medicaldevices with coaxial transmission lines with impedance at 50Ω or lowerhave high amounts of heat loss along the transmission lines. Inparticular, medical devices utilizing microwave energy transmit energythrough coaxial cables having therein a dielectric material (e.g.,polyfluorothetraethylene or PTFE) surrounding an inner conductor.Dielectric materials such as PTFE have a finite conductivity, whichresult in the undesired heating of transmission lines. This isparticularly true when one supplies the necessary amounts of energy fora sufficient period of time to enable tissue ablation. Energy deliverydevices configured to operate with optimized characteristic impedanceovercome this limitation by lacking, or substantially lacking, a soliddielectric insulator. For example, using air in place of a traditionaldielectric insulator results in an efficient device operating at 77Ω. Insome embodiments, the devices employ a near-zero conductivity dielectricmaterial (e.g., air, water, inert gases, vacuum, partial vacuum, orcombinations thereof). The overall temperature of the transmission lineswithin such devices are greatly reduced through use of coaxial oftriaxial transmission lines or with near-zero conductivity dielectricmaterials, and therefore, greatly reduce undesired tissue heating.

In addition, by providing a coaxial or triaxial transmission line with adielectric material having near-zero conductivity, and avoiding the useof typical dielectric polymers, the coaxial transmission line may bedesigned such that it can fit within small needles (e.g., 18-20 gaugeneedles) or similarly small or smaller catheters. Typically, medicaldevices configured to delivery microwave energy are designed to fitwithin large needles due to bulky dielectric materials. Microwaveablation has not been extensively applied clinically due to the largeprobe size (14 gauge) and relatively small zone of necrosis (1.6 cm indiameter) (Seki T et al., Cancer 74:817 (1994)) that is created by theonly commercial device (Microtaze, Nippon Shoji, Osaka, Japan. 2.450MHz, 1.6 mm diameter probe, 70 W for 60 seconds). Other devices use acooling external water jacket that also increases probe size and canincrease tissue damage. These large probe sizes increase the risk ofcomplications when used in the chest and abdomen.

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices having coolant passagechannels (see, e.g., U.S. Pat. No. 6,461,351, and U.S. patentapplication Ser. No. 11/728,460; herein incorporated by reference in itsentirety). In particular, the energy delivery systems of the presentinvention utilize devices with coaxial or triaxial transmission linesthat allow cooling by flowing a cooling material through the dielectricand/or the inner or outer conductor of the coaxial component. In someembodiments, coolant channels comprise part of or all of the dielectricspace. In some embodiments, the devices are configured to minimize thediameter of the device, while permitting the passage of the coolant. Insome embodiments, coolant fluid comprises dielectric material. In someembodiments, space required for a cooled transmission line is minimizedby using the dielectric material as a coolant (e.g. flowable coolant).This is accomplished, in some embodiments, by replacing strips of theinner or outer conductor and/or solid dielectric material with channelsthrough which a coolant is transferred. In some embodiments, thechannels are generated by stripping the outer or inner conductor and/orsolid dielectric material along the length of the coaxial cable from oneor more (e.g., two, three, four) zones. With the removed portions of theouter or inner conductor and/or solid dielectric material creatingchannels for transfer of the coolant, the stripped component fits withina smaller outer conductor than it did prior to removal of the outer orinner conductor and/or solid dielectric material. In other embodiments,a portion of the dielectric space is used as a coolant channel. Theseembodiments provide for smaller devices with all of the advantagesderived therefrom. In some embodiments where multiple channels areemployed, coolant transfer may be in alternative directions through oneor more of the channels. An advantage of such devices is that thediameter of the coaxial or triaxial cable does not need to be increasedto accommodate coolant. Other embodiments utilize porous dielectricmaterial through with coolant can be flowed to achieve reducedtemperature without increasing diameter. Likewise, flowing thedielectric material itself as a coolant permits cooling the coaxial ortriaxial transmission line without increasing the cross-sectionalprofile. This permits the use of cooled devices that are minimallyinvasive and permit access to regions of a body that are otherwiseinaccessible or accessible only with undesired risk. The use of coolantalso permits greater energy delivery and/or energy deliver for prolongedperiods of time. Additional cooling embodiments are described above inthe Summary of the Invention.

In some embodiments, the device has a handle attached to the device,wherein the handle is configured to, for example, control the passing ofcoolant into and out of the coolant channels. In some embodiments, thehandle automatically passes coolant into and out of the coolant channelsafter a certain amount of time and/or as the device reaches a certainthreshold temperature. In some embodiments, the handle automaticallystops passage of coolant into and out of the coolant channels after acertain amount of time and/or as the temperature of the device dropsbelow a certain threshold temperature. In some embodiments, the handleis manually controlled to adjust coolant flow.

In some embodiments, the handle has thereon one or more (e.g., 1, 2, 3,4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., display lights (e.g., LEDlights)). In some embodiments, the lights are configured to foridentification purposes. For example, in some embodiments, the lightsare used indicate whether a particular function of the device is activeor inactive. For example, where devices have multiple probes, one ormore lights is used to indicate whether any individual probe is poweredor unpowered. In some embodiments, the lights are used to identify theoccurrence of an event (e.g., the transmission of coolant through thedevice, the transmission of energy through the device, a movement of therespective probe, a change in a setting (e.g., temperature, positioning)within the device, etc.). The handles are not limited to a particularmanner of display (e.g., blinking, alternate colors, solid colors, etc).FIG. 30 shows a device 30000 with three LED lights 31000, 32000, and33000. FIG. 31 shows such a device 30000 in use wherein the device hasthree LED lights 31000, 32000, and 33000.

FIG. 5 shows a schematic drawing of a handle configured to control thepassing of coolant into and out of the coolant channels. As shown inFIG. 5, the handle 500 is engaged with a coaxial transmission line 510having a coolant channel 520. The handle 500 has therein a coolant inputchannel 530, a coolant output channel 540, a first blocking component550 (e.g., a screw or pin) configured to prevent flow through channel520 behind the blocking component and a second blocking component 560.The coolant input channel 530 is configured to provide coolant to thecoolant channel 520. The coolant output channel 540 is configured toremove coolant from the coolant channel 520 (e.g., coolant that hascirculated and removed heat from a device). The coolant input channel530 and coolant output channel 540 are not limited to particular sizesor means for providing and removing coolant. The first blockingcomponents 550 and second blocking component 560 are not limited toparticular sizes or shapes. In some embodiments, the first blockingcomponent 550 and second blocking component 560 each have a circularshape and a size that matches the diameter of the coolant input channel530 and the coolant output channel 540. In some embodiments, the firstblocking component 550 and second blocking component 560 are used toblock the backflow of coolant to a certain region of the handle 500. Insome embodiments, the blocking components are configured such that onlya portion (e.g., 1%, 5%, 10%, 20%, 50%, 75%, 85%, 95%, 99%) of thechannel is blocked. Blocking only a portion permits the user, forexample, to vary the pressure gradients within the coolant channel 520.

Energy delivery devices having coolant passage channels allow foradjustment of the characteristic impedance of the coaxial transmissionline. In particular, the dielectric properties of the coolant (or of anon-coolant material that is passed through the channel(s)) may beadjusted to alter the bulk complex permittivity of the dielectric mediumseparating the outer and inner conductors. As such, changes in thecharacteristic impedance are made during a procedure to, for example,optimize energy delivery, tissue effects, temperature, or other desiredproperties of the system, device, or application. In other embodiments,a flow material is selected prior to a procedure based on the desiredparameters and maintained throughout the entire procedure. Thus, suchdevices provide an antenna radiating in a changing dielectricenvironment to be adjusted to resonate in the changing environment to,for example, allow adaptive tuning of the antenna to ensure peakefficiency of operation. As desired, the fluid flow also allows heattransfer to and from the coaxial cable. In some embodiments, thechannels or hollowed out areas contain a vacuum or partial vacuum. Insome embodiments, impedance is varied by filling the vacuum with amaterial (e.g., any material that provides the desired result).Adjustments may be made at one or more time points or continuously.

The energy delivery devices having coolant passage channels are notlimited to particular aspects of the channels. In some embodiments, thechannel is cut through only a portion of the outer or inner conductorand/or solid dielectric material so that the flowed material is incontact with either the inner or outer conductor and the remainingdielectric material. In some embodiments, the channels are linear alongthe length of the coaxial cable. In some embodiments, the channels arenon-linear. In some embodiments, where more than one channel is used,the channels run parallel to one another. In other embodiments, thechannels are not parallel. In some embodiments, the channels cross oneanother. In some embodiments, the channels remove over 50% (e.g., 60%,70%, 80%, etc.) of the outer or inner conductor and/or solid dielectricmaterial. In some embodiments, the channels remove substantially all ofthe outer or inner conductor and/or solid dielectric material. In someembodiments, two or more channels converge to allow mixing of fluid(e.g. to induce an endothermic reaction). In some embodiments, coolantchannels comprise 1-100% of the dielectric space (e.g. 1% . . . 2% . . .5% . . . 10% . . . 20% . . . 50% . . . 90% . . . 100%).

The energy delivery devices having coolant passage channels are notlimited by the nature of the material that is flowed through the outeror inner conductor, collapsible channels, dielectric space, coolantchannels, porous dielectric material, and/or solid dielectric material.In some embodiments, the material is selected to maximize the ability tocontrol the characteristic impedance of the device, to maximize heattransfer to or from the coaxial cable, or to optimize a combination ofcontrol of the characteristic impedance and heat transfer. In someembodiments, the material that is flowed through the outer or innerconductor and/or solid dielectric material is a liquid. In someembodiments, the material is a gas. In some embodiments, the material isa combination of liquid or gas. The present invention is not limited tothe use of liquids or gasses. In some embodiments, the material is aslurry, a gel, or the like. In some embodiments, a coolant fluid isused. Any coolant fluid now known or later developed may be used.Exemplary coolant fluids include, but are not limited to, one or more ofor combinations of, water, glycol, air, inert gasses, carbon dioxide,nitrogen, helium, sulfur hexafluoride, ionic solutions (e.g., sodiumchloride with or without potassium and other ions), dextrose in water,Ringer's lactate, organic chemical solutions (e.g., ethylene glycol,diethylene glycol, or propylene glycol), oils (e.g., mineral oils,silicone oils, fluorocarbon oils), liquid metals, freons, halomethanes,liquified propane, other haloalkanes, anhydrous ammonia, sulfur dioxide.In some embodiments, the coolant fluids are pre-cooled prior to deliveryinto the energy deliver device. In some embodiments, the coolant fluidsare cooled with a cooling unit following entry into the energy deliverydevice. In some embodiments, the material passed through the dielectricmaterial is designed to generate an endothermic reaction upon contactwith an additional material.

The energy delivery devices having coolant passage channels areconfigured to permit control over the parameters of fluid infusionthrough the device. In some embodiments, the device is manually adjustedby the user (e.g., a treating physician or technician) as desired. Insome embodiments, the adjustments are automated. In some embodiments,the devices are configured with or used with sensors that provideinformation to the user or the automated systems (e.g., comprisingprocessors and/or software configured for receiving the information andadjusting fluid infusion or other device parameters accordingly).Parameters that may be regulated include, but are not limited to, speedof infusion of the fluid, concentration of ions or other components thataffect the properties of the fluid (e.g., dielectric properties, heattransfer properties, flow rate, etc.), temperature of the fluid, type offluid, mixture ratios (e.g., mixtures of gas/fluid for precise tuning orcooling). Thus, energy delivery devices having coolant passage channelsare configured to employ a feed-back loop that can change one or moredesired parameters to tune the device (e.g., antenna) more accurately,or speed up the infusion of the fluid if the device, portions of thedevice, or tissue of the subject reaches an undesired temperature (or atemperature for an undesired period of time).

The energy delivery devices having coolant passage channels providenumerous advantages over the currently available systems and devices.For example, by providing a coaxial or triaxial transmission line withchannels carved out of, and that can substantially remove the volume ofsolid dielectric material, the transmission line may be designed suchthat it can fit within very small needles (e.g., 18-20 gauge needles orsmaller). Likewise, using a portion or all of the dielectric space asboth dielectric material and coolant, the diameter of the line can bereduced. Typically, medical devices configured to delivery microwaveenergy are designed to fit within large needles due to bulky dielectricmaterials. Other devices use a cooling external water jacket that alsoincreases probe size and can increase tissue damage. These large probesizes increase the risk of complications when used in the chest andabdomen. Further, these probes cannot access high circuitous andbranched structures within a subject, due to their broad size andreduced flexibility. In some embodiments of the present invention, themaximum outer diameter of the portion of the device that enters asubject is 16-18 gauge or less (20 gauge or less).

FIG. 6 shows a transverse cross-section schematic of standard coaxialcable embodiments and embodiments of the present invention havingcoolant passages. As shown in FIG. 6, a conventional coaxial cable 600and two exemplary coaxial cables of the present invention, 610 and 620are provided. A coaxial cable is made, generally, of three separatespaces: a metallic inner conductor 630, a metallic outer conductor 650,and a space between them. The space between them is usually filled witha low-loss dielectric material 640 (e.g., polyfluorotetraethylene, orPTFE) to mechanically support the inner conductor and maintain it withthe outer conductor. The characteristic impedance of a coaxial cable isfixed by the ratio of diameters of the inner conductor and dielectricmaterial (i.e., inner diameter of the outer conductor) and thepermittivity of the space between them. Usually, the permittivity isfixed because of the solid polymer comprising it. However, inembodiments of the present invention, a fluid with variable permittivity(or conductivity) at least partially occupies this space, permitting thecharacteristic impedance of the cable to be adjusted.

Still referring to FIG. 6, in one embodiment of the present invention,the coaxial cable 610 has the outer portion of the dielectric materialremoved to create a channel between the dielectric material 640 and theouter conductor 650. In the embodiments shown, the created space isseparated into four distinct channels 670 by the addition of supportlines 660 configured to maintain the space between the outer conductor650 and the solid dielectric material 640. The support lines 660 may bemade of any desired material and may be the same or a different materialas the solid dielectric material 640. In some embodiments, so as toavoid undesired heating of the device (e.g., undesired heating of theouter conductor), the support lines 660 are made of a biocompatible andmeltable material (e.g., wax). The presence of multiple channels permitsone or more of the channels to permit flow in one direction (towards theproximal end of the cable) and one or more other channels to permit flowin the opposite direction (towards the distal end of the cable).

Still referring to FIG. 6, in another embodiment, the coaxial cable 620has a substantial portion of the solid dielectric material 640 removed.Such an embodiment may be generated, for example, by stripping away thesolid dielectric material 640 down to the surface of inner conductor 630on each of four sides. In another embodiment, strips of dielectricmaterial 640 are applied to an inner conductor 630 to create thestructure. In this embodiment, four channels 670 are created. Byremoving a substantial amount of the dielectric material 640, thediameter of the outer conductor 650 is substantially reduced. Thecorners provided by the remaining dielectric material 640 provide thesupport to maintain the position of the outer conductor 650 with respectto the inner conductor 630. In this embodiment, the overall diameter ofthe coaxial cable 620 and the device is substantially reduced.

In some embodiments, the devices have a coolant passage formed throughinsertion of a tube configured to circulate coolant through thedielectric portion or inner or outer conductors of any of the energyemission devices of the present invention. FIG. 7 shows a coolantcirculating tube 700 (e.g., coolant needle, catheter) positioned withinan energy emission device 710 having an outer conductor 720, adielectric material 730, and an inner conductor 740. As shown in FIG. 7,the tube 700 is positioned along the outside edge of the dielectricmaterial 730 and inside edge of the outer conductor 720, with the innerconductor 740 positioned approximately in the center of the dielectricmaterial 730. In some embodiments, the tube 700 is positioned within thedielectric material 730 such that it does not contact the outerconductor 720. In some embodiments, the tube 700 has multiple channels(not shown) for purposes of recirculating the coolant within the tube700 without passing the coolant into the dielectric material 730 and/orthe outer conductor 720, thereby cooling the dielectric material 730and/or the outer conductor 720 with the exterior of the tube 700.

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices employing a center fed dipolecomponent (see, e.g., U.S. patent application Ser. No. 11/728,457;herein incorporated by reference in its entirety). The devices are notlimited to particular configurations. In some embodiments, the deviceshave therein a center fed dipole for heating a tissue region throughapplication of energy (e.g., microwave energy). In some embodiments,such devices have a coaxial cable or triaxial cable connected to ahollow tube (e.g., where the interior diameter is at least 50% of theexterior diameter; e.g., where the interior diameter is substantiallysimilar to the exterior diameter). The coaxial or triaxial cable may bea standard coaxial or triaxial cable, or it may be a coaxial or triaxialcable having therein a dielectric component with a near-zeroconductivity (e.g., air). The coaxial or triaxial transmission line maycomprise one or more coolant channels within the dielectric space orbetween the second and third conductors. The tube is not limited to aparticular design configuration. In some embodiments, the tube assumesthe shape of (e.g., diameter of), for example, a 20-gauge needle. Insome embodiments, transmission lines are of a gauge less than that of a20-gauge needle. Preferably, the tube is made of a solid, conductivematerial (e.g., any number of metals, conductor-coated ceramics orpolymers, etc.). In some embodiments, the tube is constructed of abraided material (e.g. braided metal) to provide both strength andflexibility. In some embodiments, a hollow tube is configured with asharpened point or the addition of a stylet on its distal end to permitdirect insertion of the device into a tissue region without the use of,for example, a cannula. The tube is not limited to a particularcomposition (e.g., metal, plastic, ceramic). In some embodiments, thetube comprises, for example, copper or copper alloys with otherhardening metals, silver or silver alloys with other hardening metals,gold-plated copper, metal-plated Macor (machinable ceramic),metal-plated hardened polymers, and/or combinations thereof.

In some embodiments, the center fed dipole is configured to adjust theenergy delivery characteristics in response to heating so as to providea more optimal energy delivery throughout the time period of a process.In some embodiments, this is achieved by using a material that changesvolume in response to temperature changes such that the change in thevolume of the material changes to the energy delivery characteristics ofthe device. In some embodiments, for example, an expandable material isplaced in the device such that the resonant portion of the center feddipole component or the stylet is pushed distally along the device inresponse to heating. This changes the tuning of the device to maintain amore optimal energy delivery. The maximum amount of movement can beconstrained, if desired, by, for example, providing a locking mechanismthat prevents extension beyond a particular point.

The energy delivery devices employing a center fed dipole component arenot limited by the manner in which the hollow tube is connected to thecoaxial or triaxial cable. In some embodiments, a portion of the outerconductor at the distal end of the coaxial cable feedline is removed,exposing a region of solid dielectric material. The hollow tube can bepositioned onto the exposed dielectric material and attached by anymeans. In some embodiments, a physical gap between the outer conductorand the hollow tube is provided. In some embodiments, the hollow tube iscapacitively or conductively attached to the feedline at its centerpoint such that the electrical length of the hollow tube comprises afrequency-resonant structure when inserted into tissue.

In use, the energy delivery devices employing a center fed dipolecomponent are configured such that an electric field maximum isgenerated at the open distal end of the hollow tube. In someembodiments, the distal end of the hollow tube has a pointed shape so asto assist in inserting the device though a subject and into a tissueregion. In some embodiments, the entire device is hard and rigid so asto facilitate linear and direct insertion directly to a target site. Insome embodiments, the structure resonates at, for example, ˜2.45 GHz, ascharacterized by a minimum in the reflection coefficient (measured atthe proximal end of the feedline) at this frequency. By changing thedimensions of the device (e.g., length, feed point, diameter, gap, etc.)and materials (dielectric materials, conductors, etc.) of the antenna,the resonant frequency may be changed. A low reflection coefficient at adesired frequency ensures efficient transmission of energy from theantenna to the medium surrounding it.

Preferably, the hollow tube is of length λ/2, where λ is theelectromagnetic field wavelength in the medium of interest (e.g., ˜18 cmfor 2.45 GHz in liver) to resonate within the medium. In someembodiments, the length of the hollow tube is approximately λ/2, where λis the electromagnetic field wavelength in the medium of interest toresonate within the medium, such that a minimum of power reflection atthe proximal end is measured. However, deviations from this length maybe employed to generate resonant wavelengths (e.g., as the surroundingmaterials are changed). Preferably, the inner conductor of a coaxialcable is extended with its distal end at the tube center (e.g., at λ/4from the end of the tube) and configured such that the inner conductormaintains electrical contact at the tube center, although deviationsfrom this position are permitted (e.g., to generate resonantwavelengths).

The hollow tube portion of the present invention may have a wide varietyof shapes. In some embodiments, the tube is cylindrical throughout itslength. In some embodiments, tube tapers from a center position suchthat it has a smaller diameter at its end as compared to its center.Some embodiments, having a smaller point at the distal end assists inpenetrating a subject to arrive at the target region. In someembodiments, where the shape of the hollow tube deviates from acylindrical shape, the tube maintains a symmetrical structure on eitherside of its longitudinal center. However, the devices are not limited bythe shape of the hollow tube, so long as the functional properties areachieved (i.e., the ability to deliver desired energy to a targetregion).

In some embodiments, the center-fed dipole components may be added tothe distal end of a wide variety of ablation devices to provide thebenefits described herein. Likewise, a wide variety of devices may bemodified to accept the center-fed dipole components of the presentinvention.

In some embodiments, the devices have a small outer diameter. In someembodiments, the center-fed dipole component of the invention isdirectly used to insert the invasive component of the device into asubject. In some such embodiments, the device does not contain acannula, allowing for the invasive components to have a smaller outerdiameter. For example, the invasive component can be designed such thatit fits within or is the size of very small needles (e.g., 18-20 gaugeneedles or smaller).

FIG. 8 schematically shows the distal end of a device 800 (e.g., antennaof an ablation device) of the present invention that comprises a centerfed dipole component 810 of the present invention. One skilled in theart will appreciate any number of alternative configurations thataccomplish the physical and/or functional aspects of the presentinvention. As shown, the center fed dipole device 800 has therein ahollow tube 815, a coaxial transmission line 820 (e.g., a coaxialcable), and a stylet 890. The center fed dipole device 800 is notlimited to a particular size. In some embodiments, the size of thecenter fed dipole device 800 is small enough to be positioned at atissue region (e.g., a liver) for purposes of delivering energy (e.g.,microwave energy) to that tissue region.

Referring again to FIG. 8, the hollow tube 815 is not limited to aparticular material (e.g., plastic, ceramic, metal, etc.). The hollowtube 815 is not limited to a particular length. In some embodiments, thelength of the hollow tube is λ/2, where λ is the electromagnetic fieldwavelength in the medium of interest (e.g., ˜18 cm for 2.45 GHz inliver). The hollow tube 815 engages the coaxial transmission line 820such that the hollow tube 815 is attached to the coaxial transmissionline 820 (described in more detail below). The hollow tube 815 hastherein a hollow tube matter 860. The hollow tube 815 is not limited toa particular type of hollow tube matter. In some embodiments, the hollowtube matter 860 is air, fluid or a gas.

Still referring to FIG. 8, the hollow tube 815 is not limited to aparticular shape (e.g., cylindrical, triangular, squared, rectangular,etc.). In some embodiments, the shape of the hollow tube 815 is of aneedle (e.g., a 20-gauge needle, an 18-gauge needle). In someembodiments, the hollow tube 815 is divided into two portions each ofvariable length. As shown, the hollow tube 815 is divided into twoportions each of equal length (e.g., each portion having a length ofλ/4). In such embodiments, the shapes of each portion are symmetrical.In some embodiments, the hollow tube has a diameter equal to or lessthan a 20-gauge needle, a 17-gauge needle, a 12-gauge needle, etc.

Still referring to FIG. 8, the distal end of the hollow tube 815 engagesa stylet 890. The device 800 is not limited to a particular stylet 890.In some embodiments, the stylet 890 is designed to facilitatepercutaneous insertion of the device 800. In some embodiments, thesytlet 890 engages the hollow tube 815 by sliding inside the hollow tube815 such that the stylet 890 is secured.

Still referring to FIG. 8, the coaxial transmission line 820 is notlimited to a particular type of material. In some embodiments, theproximal coaxial transmission line 820 is constructed fromcommercial-standard 0.047-inch semi-rigid coaxial cable. In someembodiments, the coaxial transmission line 820 is metal-plated (e.g.,silver-plated, copper-plated), although the present invention is not solimited. The proximal coaxial transmission line 820 is not limited to aparticular length.

Still referring to FIG. 8, in some embodiments, the coaxial transmissionline 820 has a coaxial center conductor 830, a coaxial dielectricmaterial 840, and a coaxial outer conductor 850. In some embodiments,the coaxial center conductor 830 is configured to conduct cooling fluidalong its length. In some embodiments, the coaxial center conductor 830is hollow. In some embodiments, the coaxial center conductor 830 has adiameter of, for example, 0.012 inches. In some embodiments, the coaxialdielectric material 840 is polyfluorotetraethylene (PTFE). In someembodiments, the coaxial dielectric material 840 has a near-zeroconductivity (e.g., air, fluid, gas).

Still referring to FIG. 8, the distal end of the coaxial transmissionline 820 is configured to engage the proximal end of the hollow tube815. In some embodiments, the coaxial center conductor 830 and thecoaxial dielectric material 840 extend into the center of the hollowtube 815. In some embodiments, the coaxial center conductor 820 extendsfurther into the hollow tube 815 than the coaxial dielectric material840. The coaxial center conductor 820 is not limited to a particularamount of extension into the hollow tube 815. In some embodiments, thecoaxial center conductor 820 extends a length of λ/4 into the hollowtube 815. The distal end of the coaxial transmission line 820 is notlimited to a particular manner of engaging the proximal end of thehollow tube 815. In some embodiments, the proximal end of the hollowtube engages the coaxial dielectric material 840 so as to secure thehollow tube 815 with the coaxial transmission line 820. In someembodiments, where the coaxial dielectric material 840 has a near-zeroconductivity, the hollow tube 815 is not secured with the coaxialtransmission line 820. In some embodiments, the distal end of thecoaxial center conductor 830 engages the walls of the hollow tube 815directly or though contact with a conductive material 870, which may bemade of the same material as the coaxial center conductor or may be of adifferent material (e.g., a different conductive material).

Still referring to FIG. 8, in some embodiments, a gap 880 exists betweenthe distal end of the coaxial transmission line outer conductor 850 andthe hollow tube 815 thereby exposing the coaxial dielectric material840. The gap 880 is not limited to a particular size or length. In someembodiments, the gap 880 ensures an electric field maximum at theproximal end of the coaxial transmission line 880 and the distal openend of the hollow tube 815. In some embodiments, the center fed dipoledevice 810 resonates at ˜2.45 GHz, as characterized by a minimum in thereflection coefficient at this frequency. By changing the dimensions(length, feed point, diameter, gap, etc.) and materials (dielectricmaterials, conductors, etc.) of the device the resonant frequency may bechanged. A low reflection coefficient at this frequency ensuresefficient transmission of energy from the antenna to the mediumsurrounding it.

Still referring to FIG. 8, in some embodiments, the gap 880 is filledwith a material (e.g., epoxy) so bridge the coaxial transmission line820 and the hollow tube 815. The devices are not limited to a particulartype or kind of substantive material. In some embodiments, thesubstantive material does not interfere with the generation or emissionof an energy field through the device. In some embodiments, the materialis biocompatible and heat resistant. In some embodiments, the materiallacks or substantially lacks conductivity. In some embodiments, thematerial further bridges the coaxial transmission line 820 and thehollow tube 815 with the coaxial center conductor 830. In someembodiments, the substantive material is a curable resin. In someembodiments, the material is a dental enamel (e.g., XRV Herculiteenamel; see, also, U.S. Pat. Nos. 6,924,325, 6,890,968, 6,837,712,6,709,271, 6,593,395, and 6,395,803, each herein incorporated byreference in their entireties). In some embodiments, the substantivematerial is cured (e.g., cured with a curing light such as, for example,L. E. Demetron II curing light) (see, e.g., U.S. Pat. Nos. 6,994,546,6,702,576, 6,602,074 and 6,435,872). Thus, the present inventionprovides ablation devices comprising a cured enamel resin. Such a resinis biocompatible and rigid and strong.

III. Processor

In some embodiments, the energy delivery systems of the presentinvention utilize processors that monitor and/or control and/or providefeedback concerning one or more of the components of the system. In someembodiments, the processor is provided within a computer module. Thecomputer module may also comprise software that is used by the processorto carry out one or more of its functions. For example, in someembodiments, the systems of the present invention provide software forregulating the amount of microwave energy provided to a tissue regionthrough monitoring one or more characteristics of the tissue regionincluding, but not limited to, the size and shape of a target tissue,the temperature of the tissue region, and the like (e.g., through afeedback system) (see, e.g., U.S. patent application Ser. Nos.11/728,460, 11/728,457, and 11/728,428; each of which is hereinincorporated by reference in their entireties). In some embodiments, thesoftware is configured to provide information (e.g., monitoringinformation) in real time. In some embodiments, the software isconfigured to interact with the energy delivery systems of the presentinvention such that it is able to raise or lower (e.g., tune) the amountof energy delivered to a tissue region. In some embodiments, thesoftware is designed to prime coolants for distribution into, forexample, an energy delivery device such that the coolant is at a desiredtemperature prior to use of the energy delivery device. In someembodiments, the type of tissue being treated (e.g., liver) is inputtedinto the software for purposes of allowing the processor to regulate(e.g., tune) the delivery of microwave energy to the tissue region basedupon pre-calibrated methods for that particular type of tissue region.In other embodiments, the processor generates a chart or diagram basedupon a particular type of tissue region displaying characteristicsuseful to a user of the system. In some embodiments, the processorprovides energy delivering algorithms for purposes of, for example,slowly ramping power to avoid tissue cracking due to rapid out-gassingcreated by high temperatures. In some embodiments, the processor allowsa user to choose power, duration of treatment, different treatmentalgorithms for different tissue types, simultaneous application of powerto the antennas in multiple antenna mode, switched power deliverybetween antennas, coherent and incoherent phasing, etc. In someembodiments, the processor is configured for the creation of a databaseof information (e.g., required energy levels, duration of treatment fora tissue region based on particular patient characteristics) pertainingto ablation treatments for a particular tissue region based uponprevious treatments with similar or dissimilar patient characteristics.In some embodiments, the processor is operated by remote control.

In some embodiments, the processor is used to generate, for example, anablation chart based upon entry of tissue characteristics (e.g., tumortype, tumor size, tumor location, surrounding vascular information,blood flow information, etc.). In such embodiments, the processor coulddirect placement of the energy delivery device so as to achieve desiredablation based upon the ablation chart. In some embodiments, a processorcommunicates with positions sensors and/or steering mechanisms toprovide appropriate placement of systems and devices of the presentinvention.

In some embodiments a software package is provided to interact with theprocessor that allows the user to input parameters of the tissue to betreated (e.g., type of tumor or tissue section to be ablated, size,where it is located, location of vessels or vulnerable structures, andblood flow information) and then draw the desired ablation zone on a CTor other image to provide the desired results. The probes may be placedinto the tissue, and the computer generates the expected ablation zonebased on the information provided. Such an application may incorporatefeedback. For example, CT, MM, or ultrasound imaging or thermometry maybe used during the ablation. This data is fed back into the computer,and the parameters readjusted to produce the desired result.

As used herein, the terms “computer memory” and “computer memory device”refer to any storage media readable by a computer processor. Examples ofcomputer memory include, but are not limited to, random access memory(RAM), read-only memory (ROM), computer chips, optical discs (e.g.,compact discs (CDs), digital video discs (DVDs), etc.), magnetic disks(e.g., hard disk drives (HDDs), floppy disks, ZIP® disks, etc.),magnetic tape, and solid state storage devices (e.g., memory cards,“flash” media, etc.).

As used herein, the term “computer readable medium” refers to any deviceor system for storing and providing information (e.g., data andinstructions) to a computer processor. Examples of computer readablemedia include, but are not limited to, optical discs, magnetic disks,magnetic tape, solid-state media, and servers for streaming media overnetworks.

As used herein, the terms “processor” and “central processing unit” or“CPU” are used interchangeably and refer to a device that is able toread a program from a computer memory device (e.g., ROM or othercomputer memory) and perform a set of steps according to the program.

IV. Imaging Systems

In some embodiments, the energy delivery systems of the presentinvention utilize imaging systems comprising imaging devices. The energydelivery systems are not limited to particular types of imaging devices(e.g., endoscopic devices, stereotactic computer assisted neurosurgicalnavigation devices, thermal sensor positioning systems, motion ratesensors, steering wire systems, intraprocedural ultrasound, interstitialultrasound, microwave imaging, acoustic tomography, dual energy imaging,fluoroscopy, computerized tomography magnetic resonance imaging, nuclearmedicine imaging devices triangulation imaging, thermoacoustic imaging,infrared and/or laser imaging, electromagnetic imaging) (see, e.g., U.S.Pat. Nos. 6,817,976, 6,577,903, and 5,697,949, 5,603,697, andInternational Patent Application No. WO 06/005,579; each hereinincorporated by reference in their entireties). In some embodiments, thesystems utilize endoscopic cameras, imaging components, and/ornavigation systems that permit or assist in placement, positioning,and/or monitoring of any of the items used with the energy systems ofthe present invention.

In some embodiments, the energy delivery systems provide software isconfigured for use of imaging equipment (e.g., CT, MM, ultrasound). Insome embodiments, the imaging equipment software allows a user to makepredictions based upon known thermodynamic and electrical properties oftissue, vasculature, and location of the antenna(s). In someembodiments, the imaging software allows the generation of athree-dimensional map of the location of a tissue region (e.g., tumor,arrhythmia), location of the antenna(s), and to generate a predicted mapof the ablation zone.

In some embodiments, the imaging systems of the present invention areused to monitor ablation procedures (e.g., microwave thermal ablationprocedures, radio-frequency thermal ablation procedures). The presentinvention is not limited to a particular type of monitoring. In someembodiments, the imaging systems are used to monitor the amount ofablation occurring within a particular tissue region(s) undergoing athermal ablation procedure. In some embodiments, the monitoring operatesalong with the ablation devices (e.g., energy delivery devices) suchthat the amount of energy delivered to a particular tissue region isdependent upon the imaging of the tissue region. The imaging systems arenot limited to a particular type of monitoring. The present invention isnot limited to what is being monitored with the imaging devices. In someembodiments, the monitoring is imaging blood perfusion for a particularregion so as to detect changes in the region, for example, before,during and after a thermal ablation procedure. In some embodiments, themonitoring includes, but is not limited to, MRI imaging, CT imaging,ultrasound imaging, nuclear medicine imaging, and fluoroscopy imaging.For example, in some embodiments, prior to a thermal ablation procedure,a contrast agent (e.g., iodine or other suitable CT contrast agent;gadolinium chelate or other suitable MRI contrast agent, microbubbles orother suitable ultrasound constrast agent, etc.) is supplied to asubject (e.g., a patient) and the contrast agent perfusing through aparticular tissue region that is undergoing the ablation procedure ismonitored for blood perfusion changes. In some embodiments, themonitoring is qualitative information about the ablation zone properties(e.g., the diameter, the length, the cross-sectional area, the volume).The imaging system is not limited to a particular technique formonitoring qualitative information. In some embodiments, techniques usedto monitor qualitative information include, but are not limited to,non-imaging techniques (e.g., time-domain reflectometry, time-of-flightpulse detection, frequency-modulated distance detection, eigenmode orresonance frequency detection or reflection and transmission at anyfrequency, based on one interstitial device alone or in cooperation withother interstitial devices or external devices). In some embodiments,the interstitial device provides a signal and/or detection for imaging(e.g., electro-acoustic imaging, electromagnetic imaging, electricalimpedance tomography). In some embodiments, non-imaging techniques areused to monitor the dielectric properties of the medium surrounding theantenna, detect an interface between the ablated region and normaltissue through several means, including resonance frequency detection,reflectometry or distance-finding techniques, powerreflection/transmission from interstitial antennas or external antennas,etc. In some embodiments, the qualitative information is an estimate ofablation status, power delivery status, and/or simple go/no-go checks toensure power is being applied. In some embodiments, the imaging systemsare designed to automatically monitor a particular tissue region at anydesired frequency (e.g., per second intervals, per one-minute intervals,per ten-minute intervals, per hour-intervals, etc.). In someembodiments, the present invention provides software designed toautomatically obtain images of a tissue region (e.g., MRI imaging, CTimaging, ultrasound imaging, nuclear medicine imaging, fluoroscopyimaging), automatically detect any changes in the tissue region (e.g.,blood perfusion, temperature, amount of necrotic tissue, etc.), andbased on the detection to automatically adjust the amount of energydelivered to the tissue region through the energy delivery devices.Likewise, an algorithm may be applied to predict the shape and size ofthe tissue region to be ablated (e.g., tumor shape) such that the systemrecommends the type, number, and location of ablation probes toeffectively treat the region. In some embodiments, the system isconfigured to with a navigation or guidance system (e.g., employingtriangulation or other positioning routines) to assist in or direct theplacement of the probes and their use.

For example, such procedures may use the enhancement or lack ofenhancement of a contrast material bolus to track the progress of anablation or other treatment procedure. Subtraction methods may also beused (e.g., similar to those used for digital subtraction angiography).For example, a first image may be taken at a first time point.Subsequent images subtract out some or all of the information from thefirst image so that changes in tissue are more readily observed.Likewise, accelerated imaging techniques may be used that apply “undersampling” techniques (in constrast to Nyquist sampling). It iscontemplated that such techniques provide excellent signal-to-noiseusing multiple low resolutions images obtained over time. For example,an algorithm called HYPER (highly constrained projection reconstruction)is available for MRI that may be applied to embodiments of the systemsof the invention.

As thermal-based treatments coagulate blood vessels when tissuetemperatures exceed, for example, 50° C., the coagulation decreasesblood supply to the area that has been completely coagulated. Tissueregions that are coagulated do not enhance after the administration ofcontrast. In some embodiments, the present invention utilizes theimaging systems to automatically track the progress of an ablationprocedure by giving, for example, a small test injection of contrast todetermine the contrast arrival time at the tissue region in question andto establish baseline enhancement. In some embodiments, a series ofsmall contrast injections is next performed following commencement ofthe ablation procedure (e.g., in the case of CT, a series of up tofifteen 10 ml boluses of 300 mgI/ml water soluble contrast is injected),scans are performed at a desired appropriate post-injection time (e.g.,as determined from the test injection), and the contrast enhancement ofthe targeted area is determined using, for example, a region-of-interest(ROI) to track any one of a number of parameters including, but notlimited to, attenuation (Hounsfield Units [HU]) for CT, signal (MM),echogenicity (ultrasound), etc. The imaged data is not limited to aparticular manner of presentation. In some embodiments, the imaging datais presented as color-coded or grey scale maps or overlays of the changein attenuation/signal/echogenicity, the difference between targeted andnon-targeted tissue, differences in arrival time of the contrast bolusduring treatment, changes in tissue perfusion, and any other tissueproperties that can be measured before and after the injection ofcontrast material. The methods of the present invention are not limitedto selected ROI's, but can be generalized to all pixels within anyimage. The pixels can be color-coded, or an overlay used to demonstratewhere tissue changes have occurred and are occurring. The pixels canchange colors (or other properties) as the tissue property changes, thusgiving a near real-time display of the progress of the treatment. Thismethod can also be generalized to 3d/4d methods of image display.

In some embodiments, the area to be treated is presented on a computeroverlay, and a second overlay in a different color or shading yields anear real-time display of the progress of the treatment. In someembodiments, the presentation and imaging is automated so that there isa feedback loop to a treatment technology (RF, MW, HIFU, laser, cryo,etc) to modulate the power (or any other control parameter) based on theimaging findings. For example, if the perfusion to a targeted area isdecreased to a target level, the power could be decreased or stopped.For example, such embodiments are applicable to a multiple applicatorsystem as the power/time/frequency/duty cycle, etc. is modulated foreach individual applicator or element in a phased array system to createa precisely sculpted zone of tissue treatment. Conversely, in someembodiments, the methods are used to select an area that is not to betreated (e.g., vulnerable structures that need to be avoided such asbile ducts, bowel, etc.). In such embodiments, the methods monitortissue changes in the area to be avoided, and warn the user (e.g.,treating physician) using alarms (e.g., visible and/or audible alarms)that the structure to be preserved is in danger of damage. In someembodiments, the feedback loop is used to modify power or any otherparameter to avoid continued damage to a tissue region selected not tobe treated. In some embodiments, protection of a tissue region fromablation is accomplished by setting a threshold value such as a targetROI in a vulnerable area, or using a computer overlay to define a “notreatment” zone as desired by the user.

V. Tuning Systems

In some embodiments, the energy delivery systems of the presentinvention utilize tuning elements for adjusting the amount of energydelivered to the tissue region. In some embodiments, the tuning elementis manually adjusted by a user of the system. In some embodiments, atuning system is incorporated into an energy delivery device so as topermit a user to adjust the energy delivery of the device as desired(see, e.g., U.S. Pat. Nos. 5,957,969, 5,405,346; each hereinincorporated by reference in their entireties). In some embodiments, thedevice is pretuned to the desired tissue and is fixed throughout theprocedure. In some embodiments, the tuning system is designed to matchimpedance between a generator and an energy delivery device (see, e.g.,U.S. Pat. No. 5,364,392; herein incorporated by reference in itsentirety). In some embodiments, the tuning element is automaticallyadjusted and controlled by a processor of the present invention (see,e.g., U.S. Pat. No. 5,693,082; herein incorporated by reference in itsentirety). In some embodiments, a processor adjusts the energy deliveryover time to provide constant energy throughout a procedure, taking intoaccount any number of desired factors including, but not limited to,heat, nature and/or location of target tissue, size of lesion desired,length of treatment time, proximity to sensitive organ areas or bloodvessels, and the like. In some embodiments, the system comprises asensor that provides feedback to the user or to a processor thatmonitors the function of the device continuously or at time points. Thesensor may record and/or report back any number of properties,including, but not limited to, heat at one or more positions of acomponents of the system, heat at the tissue, property of the tissue,and the like. The sensor may be in the form of an imaging device such asCT, ultrasound, magnetic resonance imaging, or any other imaging device.In some embodiments, particularly for research application, the systemrecords and stores the information for use in future optimization of thesystem generally and/or for optimization of energy delivery underparticular conditions (e.g., patient type, tissue type, size and shapeof target region, location of target region, etc.).

VI. Temperature Adjustment Systems

In some embodiments, the energy delivery systems of the presentinvention utilize coolant systems so as to reduce undesired heatingwithin and along an energy delivery device (e.g., tissue ablationcatheter). The systems of the present invention are not limited to aparticular cooling system mechanism. In some embodiments, the systemsare designed to circulate a coolant (e.g., air, liquid, etc.) throughoutan energy delivery device such that the coaxial transmission line(s) ortriaxial transmission line(s) and antenna(e) temperatures are reduced.In some embodiments, the systems utilize energy delivery devices havingtherein channels designed to accommodate coolant circulation. In someembodiments, the systems provide a coolant sheath wrapped around theantenna or portions of the antenna for purposes of cooling the antennaexternally (see, e.g., U.S. patent application Ser. No. 11/053,987;herein incorporated by reference in its entirety). In some embodiments,a coolant sheath comprises a collapsible material (e.g. boPET) whichadopts a low cross-sectional profile when collapsed (e.g. for insertionand/or deployment) and is expanded upon flow of coolant through thesheath (SEE FIGS. 32I and 32J). In some embodiments, a coolant sheathalso functions as the outer conductor of a coaxial cable, or the outeror second conductor (middle conductor) of a triaxial cable. In someembodiments, the systems utilize energy delivery devices having aconductive covering around the antenna for purposes of limitingdissipation of heat onto surrounding tissue (see, e.g., U.S. Pat. No.5,358,515; herein incorporated by reference in its entirety). In someembodiments, upon circulation of the coolant, it is exported into, forexample, a waste receptacle. In some embodiments, upon circulation ofthe coolant it is recirculated. In some embodiments, the coolant is agas circulated at or near its critical point. In some embodiments, thegas delivered at or near its critical point is carbon dioxide gas. Insome embodiments, the energy delivery devices are configured to compresstransported coolants (e.g., carbon dioxide gas at or near its criticalpoint) at a desired pressure so as to retain the coolant at or near itscritical point.

In some embodiments, the systems utilize expandable balloons inconjunction with energy delivery devices for purposes of urging tissueaway from the surface of the antenna(e) (see, e.g., U.S. patentapplication Ser. No. 11/053,987; herein incorporated by reference in itsentirety).

In some embodiments, the systems utilize devices configured to attachonto an energy delivery device for purposes of reducing undesiredheating within and along the energy delivery device (see, e.g., U.S.patent application Ser. No. 11/237,430; herein incorporated by referencein its entirety).

In some embodiments, coolant channels may be of any suitableconfiguration (SEE FIG. 32), and find use with any configuration ofenergy delivery device and/or system (e.g. coaxial, triaxial,multiple-catheter, etc.). In some embodiments, the dielectric materialof a coaxial transmission line (or the dielectric material of thecoaxial portion (e.g. inner conductor, dielectric material, secondconductor) of a triaxial transmission line) comprises a fluid (e.g. gas(e.g. air, CO₂, etc.) or liquid) which also acts as a coolant for thetransmission line (SEE FIG. 32A). In some embodiments, the coolant(dielectric material) is flowed through one or more regions between theinner conductor and a second conductor (e.g. outer conductor). In someembodiments, a transmission line comprises one or more coolant channels(e.g. 1 channel, 2 channels, 3, channels, 4 channels, 5 channels, 6channels, 7, channels, 8 channels, 9 channels, 10 channels, etc.)through which dielectric material and/or coolant is flowed. In someembodiments, coolant channels converge and/or diverge to provide optimalcooling and/or mixing of two or more coolant components (e.g. to provideand endothermic colling reaction). In some embodiments, one or morechannels provide coolant flow from the proximal end of a device to thedistal end (coolant channel), and one or more channels provide coolantfrom the distal end of a device to the proximal end (e.g. returnchannel). In some embodiments, cooled dielectric material (e.g. coolantliquid, air, CO₂, etc.) is flowed from a pump located near the proximalend of a device or system through one or more coolant channels along thetransmission line. In some embodiments, dielectric material flowed tothe distal end of a transmission line is transferred to a return channeland flowed back to the proximal end. In some embodiments, dielectricmaterial is capable of cooling a transmission line in both a coolantchannel and return channel. In some embodiments, a coolant and/ordielectric material fills a channel without continuous flow. In someembodiments, a coolant and/or dielectric material is pumped into and outof a single channel. In some embodiments, dielectric material absorbsheat generated by energy transmission and carries it away from thetransmission line as dielectric material is flowed along thetransmission line and out the proximal end. In some embodiments, aporous dielectric material allows coolant to flow (e.g.mono-directionally, bi-directionally, etc.) directly through thedielectric material (SEE FIG. 32H).

In some embodiments, energy delivery devices utilize reduced temperatureenergy patterns to reduce undesired heating along the length of thetransmission line. In some embodiments, constant low power energytransmission provides sufficient energy at the target site (e.g.sufficient for effective tumor ablation) without undue heating along thepath of the transmission line. In some embodiments, energy is deliveredin a pulse pattern to provide bursts of sufficient energy at the targetsite (e.g. sufficient for effective tumor ablation) with less heatbuild-up along the transmission line than continuous delivery. In someembodiments, the length and intensity of the pulse-pattern are set bymonitoring temperature along the transmission line or in the tissuesurrounding the transmission line. In some embodiments, a pulse patternis predetermined to balance the amount of energy delivered to the targetsite with the amount of heat release along the transmission line. Insome embodiments, any suitable pulse pattern will find use with thedevices, systems, and methods of the present invention. In someembodiments, an ablation algorithm is calculated or determined based ona combination of time (e.g. of treatment, of pulses, of time betweenpulses), power (e.g. power generated, power delivered, power lost,etc.), and temperature monitoring.

In some embodiments, an energy delivery device comprises a capacitorand/or energy gate at the distal end of the transmission line. Thecapacitor and/or gate delivers energy (e.g. microwave energy) to thetarget site once a threshold of energy has built up behind the capacitorand/or gate. Low level energy is delivered along the transmission line,thereby reducing heat build-up along the pathway. Once sufficient energyhas built up at the capacitor and/or gate, a high energy burst of energy(e.g. microwave energy) is delivered to the target site. The capacitorand/or gate delivery method has the advantage of reduced heating alongthe transmission path due to the low level energy transfer, as well asbursts of high energy being delivered at the target site (e.g.sufficient for tumor ablation).

In some embodiments, all or a portion of the energy generating circuitryis located at one or more points along the transmission line. In someembodiments, all or a portion of the microwave generating circuitry islocated at one or more points along the transmission line. In someembodiments, generating energy (e.g. microwave energy) at one or morepoints along the transmission line reduces the distance the energy needsto travel, thereby reducing energy loss, and undesired heat generation.In some embodiments, generating energy (e.g. microwave energy) at one ormore points along the transmission line allows for operating at reducedenergy levels while providing the same energy level to the treatmentsite.

VII. Identification Systems

In some embodiments, the energy delivery systems of the presentinvention utilize identification elements (e.g., RFID elements,identification rings (e.g., fidicials), barcodes, etc.) associated withone or more components of the system. In some embodiments, theidentification element conveys information about a particular componentof the system. The present invention is not limited by the informationconveyed. In some embodiments, the information conveyed includes, but isnot limited to, the type of component (e.g., manufacturer, size, energyrating, tissue configuration, etc.), whether the component has been usedbefore (e.g., so as to ensure that non-sterile components are not used),the location of the component, patient-specific information and thelike. In some embodiments, the information is read by a processor of thepresent invention. In some such embodiments, the processor configuresother components of the system for use with, or for optimal use with,the component containing the identification element.

In some embodiments, the energy delivery devices have thereon markings(e.g., scratches, color schemes, etchings, painted contrast agentmarkings, identification rings (e.g., fidicials), and/or ridges) so asto improve identification of a particular energy delivery device (e.g.,improve identification of a particular device located in the vicinity ofother devices with similar appearances). The markings find particularuse where multiple devices are inserted into a patient. In such cases,particularly where the devices may cross each other at various angles,it is difficult for the treating physician to associate which proximalend of the device, located outside of the patient body, corresponds towhich distal end of the device, located inside the patient body. In someembodiments, a marking (e.g., a number) a present on the proximal end ofthe device so that it is viewable by the physician's eyes and a secondmarking (e.g., that corresponds to the number) is present on the distalend of the device so that it is viewable by an imaging device whenpresent in the body. In some embodiments, where a set of antennas isemployed, the individual members of the set are numbered (e.g., 1, 2, 3,4, etc.) on both the proximal and distal ends. In some embodiments,handles are numbered, a matching numbered detachable (e.g., disposable)antennas are connected to the handles prior to use. In some embodiments,a processor of the system ensures that the handles and antennas areproperly matched (e.g., by RFID tag or other means). In someembodiments, where the antenna are disposable, the system provides awarning if a disposable component is attempted to be re-used, when itshould have been discarded. In some embodiments, the markings improveidentification in any type of detection system including, but notlimited to, MRI, CT, and ultrasound detection.

The energy delivery systems of the present invention are not limited toparticular types of tracking devices. In some embodiments, GPS and GPSrelated devices are used. In some embodiments, RFID and RFID relateddevices are used. In some embodiments, barcodes are used.

In such embodiments, authorization (e.g., entry of a code, scanning of abarcode) prior to use of a device with an identification element isrequired prior to the use of such a device. In some embodiments, theinformation element identifies that a components has been used beforeand sends information to the processor to lock (e.g. block) use ofsystem until a new, sterile component is provided.

VIII. Temperature Monitoring Systems

In some embodiments, the energy delivering systems of the presentinvention utilize temperature monitoring systems. In some embodiments,temperature monitoring systems are used to monitor the temperature of anenergy delivery device (e.g., with a temperature sensor). In someembodiments, temperature monitoring systems are used to monitor thetemperature of a tissue region (e.g., tissue being treated, surroundingtissue). In some embodiments, the temperature monitoring systems aredesigned to communicate with a processor for purposes of providingtemperature information to a user or to the processor to allow theprocessor to adjust the system appropriately. In some embodiments,temperatures are monitored at several points along the antenna toestimate ablation status, cooling status or safety checks. In someembodiments, the temperatures monitored at several points along theantenna are used to determine, for example, the geographicalcharacteristics of the ablation zone (e.g., diameter, depth, length,density, width, etc.) (e.g., based upon the tissue type, and the amountof power used in the energy delivery device). In some embodiments, thetemperatures monitored at several points along the antenna are used todetermine, for example, the status of the procedure (e.g., the end ofthe procedure). In some embodiments, temperature is monitored usingthermocouples or electromagnetic means through the interstitial antenna.In some embodiments, data collected from temperature monitoring is usedto initiate one or more cooling procedures described herein (e.g.coolant flow, lowered power, pulse program, shutoff, etc.).

IX. Procedure Device Hubs

The system of the present invention may further employ one or moreadditional components that either directly or indirectly take advantageof or assist the features of the present invention. For example, in someembodiments, one or more monitoring devices are used to monitor and/orreport the function of any one or more components of the system.Additionally, any medical device or system that might be used, directlyor indirectly, in conjunction with the devices of the present inventionmay be included with the system. Such components include, but are notlimited to, sterilization systems, devices, and components, othersurgical, diagnostic, or monitoring devices or systems, computerequipment, handbooks, instructions, labels, and guidelines, roboticequipment, and the like.

In some embodiments, the systems employ pumps, reservoirs, tubing,wiring, or other components that provide materials on connectivity ofthe various components of the systems of the present invention. Forexample, any type of pump may be used to supply gas or liquid coolantsto the antennas of the present invention. Gas or liquid handling tankscontaining coolant may be employed in the system. In some embodiments,more than one tank is used such that as one tank becomes empty,additional tanks will be used automatically so as to prevent adisruption in a procedure (e.g., as one CO₂ tank is drained empty, asecond CO₂ tanks is used automatically thereby preventing proceduredisruption). In certain embodiments, the energy delivery systems (e.g.,the energy delivery device, the processor, the power supply, the imagingsystem, the temperature adjustment system, the temperature monitoringsystem, and/or the identification systems) and all related energydelivery system utilization sources (e.g., cables, wires, cords, tubes,pipes providing energy, gas, coolant, liquid, pressure, andcommunication items) are provided in a manner that reduces undesiredpresentation problems (e.g., tangling, cluttering, and sterilitycompromise associated with unorganized energy delivery systemutilization sources). The present invention is not limited to aparticular manner of providing the energy delivery systems and energydelivery system utilization sources such that undesired presentationproblems are reduced. In some embodiments, as shown in FIG. 13, theenergy delivery systems and energy delivery system utilization sourcesare organized with an import/export box 1300, a transport sheath 1310,and a procedure device pod 1320. In some embodiments, energy deliverysystems and energy delivery system utilization sources organized with animport/export box, transport sheath, and procedure device pod provideseveral benefits. Such benefits include, but are not limited to,decreasing the number of cords traversing between a generator (e.g., amicrowave generator) and a patient (e.g., decreasing the number of cordson the floor), de-cluttering the sterile environment and procedure room,increasing patient safety by having the energy delivery systems “move”with a patient thereby preventing device dislodgement (e.g., antennadislodgement), increasing power delivery efficiency by reducing theenergy travel distance within the energy delivery device, and reducingdisposable costs by shortening the length of the disposable cables.

The present invention is not limited to a particular type or kind ofimport/export box. In some embodiments, the import/export box containsthe power supply and coolant supply. In some embodiments, theimport/export box is located outside of a sterile field in which thepatient is being treated. In some embodiments, the import/export box islocated outside of the room in which the patient is being treated. Insome embodiments, one or more cables connect the import/export box to aprocedure device pod. In some embodiments, a single cable is used (e.g.,a transport sheath). For example, in some such embodiments, a transportsheath contains components for delivery of both energy and coolant toand/or from the import/export box. In some embodiments, the transportsheath connects to the procedure device pod without causing a physicalobstacle for medical practitioners (e.g., travels under the floor,overhead, etc). In some embodiments, the cable is a low-loss cable(e.g., a low-loss cable attaching the power supply to the proceduredevice hub). In some embodiments, the low-loss cable is secured (e.g.,to the procedure device hub, to a procedure table, to a ceiling) so asto prevent injury in the event of accidental pulling of the cable. Insome embodiments, the cable connecting the power generator (e.g.,microwave power generator) and the procedure device hub is low-lossreusable cable. In some embodiments, the cable connecting the proceduredevice hub to the energy delivery device is flexible disposable cable.

The present invention is not limited to a particular type or kind ofprocedure device pod. In some embodiments, the procedure device pod isconfigured to receive power, coolant, or other elements from theimport/export box or other sources. In some embodiments, the proceduredevice pod provides a control center, located physically near thepatient, for any one or more of: delivering energy to a medical device,circulating coolant to a medical device, collecting and processing data(e.g., imaging data, energy delivery data, safety monitoring data,temperature data, and the like), and providing any other function thatfacilitates a medical procedure. In some embodiments, the proceduredevice pod is configured to engage the transport sheath so as to receivethe associated energy delivery system utilization sources. In someembodiments, the procedure device pod is configured to receive anddistribute the various energy delivery system utilization sources to theapplicable devices (e.g., energy delivery devices, imaging systems,temperature adjustment systems, temperature monitoring systems, and/oridentification systems). For example, in some embodiments, the proceduredevice pod is configured to receive microwave energy and coolant fromenergy delivery system utilization sources and distribute the microwaveenergy and coolant to an energy delivery device. In some embodiments,the procedure device pod is configured to turn on or off, calibrate, andadjust (e.g., automatically or manually) the amount of a particularenergy delivery system utilization source as desired. In someembodiments, the procedure device pod has therein a power splitter foradjusting (e.g., manually or automatically turning on, turning off,calibrating) the amount of a particular energy delivery systemutilization source as desired. In some embodiments, the procedure devicepod has therein software designed to provide energy delivery systemutilization sources in a desired manner. In some embodiments, theprocedure device pod has a display region indicating associatedcharacteristics for each energy delivery system utilization source(e.g., which devices are presently being used/not used, the temperaturefor a particular body region, the amount of gas present in a particularCO₂ tank, etc.). In some embodiments, the display region has touchcapability (e.g., a touch screen). In some embodiments, the processorassociated with the energy delivery system is located in the proceduredevice pod. In some embodiments, the power supply associated with theenergy delivery systems is located within the procedure device pod. Insome embodiments, the procedure device pod has a sensor configured toautomatically inhibit one or more energy delivery system utilizationsources upon the occurrence of an undesired event (e.g., undesiredheating, undesired leak, undesired change in pressure, etc.). In someembodiments, the weight of the procedure device hub is such that itcould be placed onto a patient without causing discomfort and/or harm tothe patient (e.g., less than 15 pounds, less than 10 pounds, less than 5pounds).

The procedure device pods of the present invention are not limited toparticular uses or uses within particular settings. Indeed, theprocedure device pods are designed for use in any setting wherein theemission of energy is applicable. Such uses include any and all medical,veterinary, and research applications. In addition, the procedure devicepods may be used in agricultural settings, manufacturing settings,mechanical settings, or any other application where energy is to bedelivered. In some embodiments, the procedure device pods are used inmedical procedures wherein patient mobility is not restricted (e.g., CTscanning, ultrasound imaging, etc.).

In some embodiments, the procedure device pod is designed for locationwithin a sterile setting. In some embodiments, the procedure device podis positioned on a patient's bed, a table that the patient is on (e.g.,a table used for CT imaging, ultrasound imaging, MRI imaging, etc.), orother structure near the patient (e.g., the CT gantry). In someembodiments, the procedure device pod is positioned on a separate table.In some embodiments, the procedure device pod is attached to a ceiling.In some embodiments, the procedure device pod is attached to a ceilingsuch that a user (e.g., a physician) may move it into a desired position(thereby avoiding having to position the energy delivery systemutilization sources (e.g., cables, wires, cords, tubes, pipes providingenergy, gas, coolant, liquid, pressure, and communication items) on ornear a patient while in use). In some embodiments, the procedure devicehub is positioned to lay on a patient (e.g., on a patient's legs,thighs, waist, chest). In some embodiments, the procedure device hub ispositioned above a patient's head or below a patient's feet. In someembodiments, the procedure device hub has Velcro permitting attachmentonto a desired region (e.g., a procedure table, a patient's drape and/orgown).

In some embodiments, the procedure device hub is configured forattachment to a procedure strap used for medical procedures (e.g., a CTsafety strap). In some embodiments, the procedure strap attaches to aprocedure table (e.g., a CT table) (e.g., through a slot on the sides ofthe procedure table, through Velcro, through adhesive, through suction)and is used to secure a patient to the procedure table (e.g., throughwrapping around the patient and connecting with, for example, Velcro).The procedure device hub is not limited to a particular manner ofattachment with a procedure strap. In some embodiments, the proceduredevice hub is attached to the procedure strap. In some embodiments, theprocedure device hub is attached to a separate strap permittingreplacement of the procedure strap. In some embodiments, the proceduredevice hub is attached to a separate strap configured to attach to theprocedure strap. In some embodiments, the procedure device hub isattached to a separate strap configured to attach to any region of theprocedure table. In some embodiments, the procedure device hub isattached to a separate strap having insulation and/or padding to ensurepatient comfort. FIG. 18 shows a procedure device hub connected to aprocedure table strap.

In some embodiments, the procedure device hub is configured forattachment to a procedure ring. The present invention is not limited toa particular type or kind of procedure ring. In some embodiments, theprocedure ring is configured for placement around a patient (e.g.,around a patient's torso, head, feet, arm, etc.). In some embodiments,the procedure ring is configured to attach to a procedure table (e.g., aCT table). The procedure device ring is not limited to a particularshape. In some embodiments, the procedure device ring is, for example,oval, circular, rectangular, diagonal, etc. In some embodiments, theprocedure device ring is approximately half of a cyclical shape (e.g.,25% of a cyclical shape, 40% of a cyclical shape, 45% of a cyclicalshape, 50% of a cyclical shape, 55 of a cyclical shape, 60 of a cyclicalshape, 75 of a cyclical shape). In some embodiments, the procedure ringis, for example, metal, plastic, graphite, wood, ceramic, or anycombination thereof. The procedure device hub is not limited to aparticular manner of attachment to the procedure ring. In someembodiments, the procedure device hub attaches onto the procedure ring(e.g., with Velcro, with snap-ons, with an adhesive agent). In someembodiments utilizing low-loss cables, the low-loss cables additionalattach onto the procedure ring. In some embodiments, the size of theprocedure ring can be adjusted (e.g., retracted, extended) toaccommodate the size of a patient. In some embodiments, additional itemsmay be attached to the procedure ring. In some embodiments, theprocedure ring may be easily moved to and from the vicinity of apatient.

In some embodiments, the procedure device hub is configured forattachment onto a custom sterile drape. The present invention is notlimited to a particular type or kind of custom sterile drape. In someembodiments, the custom sterile drape is configured for placement onto apatient (e.g., onto a patient's torso, head, feet, arm, entire body,etc.). In some embodiments, the custom sterile drape is configured toattach to a procedure table (e.g., a CT table). The custom sterile drapeis not limited to a particular shape. In some embodiments, the customsterile drape is, for example, oval, circular, rectangular, diagonal,etc. In some embodiments, the shape of the custom sterile drape is suchthat it accommodates a particular body region of a patient. In someembodiments, the procedure ring is, for example, cloth, plastic, or anycombination thereof. The procedure device hub is not limited to aparticular manner of attachment to the custom sterile drape. In someembodiments, the procedure device hub attaches onto the custom steriledrape (e.g., with Velcro, with snap-ons, with an adhesive agent, clamps(e.g., alligator clamps)). In some embodiments utilizing low-losscables, the low-loss cables additional attach onto the custom steriledrape. In some embodiments, additional items may be attached to thecustom sterile drape. In some embodiments, the custom sterile drape maybe easily moved to and from the vicinity of a patient. In someembodiments, the custom sterile drape has one more fenestrations forpurposes of performing medical procedures. FIG. 19 shows a customsterile drape with a fenestration and a cable inserted through thefenestration. FIG. 20 shows an energy delivery system of the presentinvention having a generator connected to a procedure device hub via acable, where the procedure device hub is secured to a procedure table(e.g., via a procedure table strap). Moreover, as shown in FIG. 20, acustom sterile drape is positioned over a patient lying on the proceduretable, where the custom sterile drape has a fenestration.

In some embodiments, the procedure device hub is configured with legsfor positioning the hub in the vicinity of a patient. In someembodiments, the procedure device hub has adjustable legs (e.g., therebyallowing positioning of the procedure device hub in a variety ofpositions). In some embodiments, the procedure device hub has threeadjustable legs thereby allowing the device to be positioned in varioustri-pod positions. In some embodiments, the legs have therein Velcropermitting attachment onto a desired region (e.g., a procedure table, apatient's drape and/or gown). In some embodiments, the legs are formedfrom a springy material configured to form an arc over the proceduretable (e.g., CT table) and squeeze the rails of the procedure table. Insome embodiments, the legs are configured to attach onto the rails ofthe procedure table.

In some embodiments, the procedure device pod is configured tocommunicate (wirelessly or via wire) with a processor (e.g., a computer,with the Internet, with a cellular phone, with a PDA). In someembodiments, the procedure device hub may be operated via remotecontrol. In some embodiments, the procedure device pod has thereon oneor more lights. In some embodiments, the procedure device hub provides adetectable signal (e.g., auditory, visual (e.g., pulsing light)) whenpower is flowing from the procedure device hub to an energy deliverydevice. In some embodiments, the procedure device hub has an auditoryinput (e.g., an MP3 player). In some embodiments, the procedure devicehub has speakers for providing sound (e.g., sound from an MP3 player).In some embodiments, the procedure device hub has an auditory output forproviding sound to an external speaker system. In some embodiments, theuse of a procedure device pod permits the use of shorter cables, wires,cords, tubes, and/or pipes (e.g., less than 4 feet, 3 feet, 2 feet). Insome embodiments, the procedure device pod and/or one more componentsconnected to it, or portions thereof are covered by a sterile sheath. Insome embodiments, the procedure device hub has a power amplifier forsupplying power (e.g., to an energy delivery device).

In some embodiments, the procedure device pod is configured to compresstransported coolants (e.g., CO₂) at any desired pressure so as to, forexample, retain the coolant at a desired pressure (e.g., the criticalpoint for a gas) so as to improve cooling or temperature maintenance.For example, in some embodiments, a gas is provided at or near itscritical point for the purpose of maintaining a temperature of a device,line, cable, or other component at or near a constant, definedtemperature. In some such embodiments, a component is not cooled per se,in that its temperature does not drop from a starting temperature (e.g.,room temperature), but instead is maintained at a constant temperaturethat is cooler than where the component would be, but for theintervention. For example, CO₂ may be used at or near its critical point(e.g., 31.1 Celsius at 78.21 kPa) to maintain temperature so thatcomponents of the system are sufficiently cool enough not to burntissue, but likewise are not cooled or maintained significantly belowroom temperature or body temperature such skin in contact with thecomponent freezes or is otherwise damaged by cold. Using suchconfigurations permits the use of less insulation, as there are not“cold” components that must be shielded from people or from the ambientenvironment. In some embodiments, the procedure device pod has aretracting element designed to recoil used and/or unused cables, wires,cords, tubes, and pipes providing energy, gas, coolant, liquid,pressure, and/or communication items. In some embodiments, the proceduredevice pod is configured to prime coolants for distribution into, forexample, an energy delivery device such that the coolant is at a desiredtemperature prior to use of the energy delivery device. In someembodiments, the procedure device pod has therein software configured toprime coolants for distribution into, for example, an energy deliverydevice such that the system is at a desired temperature prior to use ofthe energy delivery device. In some embodiments, the circulation ofcoolants at or near critical point permits cooling of the electronicelements of the energy delivery devices without having to use additionalcooling mechanisms (e.g., fans).

In one illustrative embodiment, an import/export box contains one ormore microwave power sources and a coolant supply (e.g., pressurizedcarbon dioxide gas). This import/export box is connected to a singletransport sheath that delivers both the microwave energy and coolant toa procedure device pod. The coolant line or the energy line within thetransport sheath may be wound around one another to permit maximumcooling of the transport sheath itself. The transport sheath is run intothe sterile field where a procedure is to take place along the floor ina location that does not interfere with the movement of the medical teamattending to the patient. The transport sheath connects to a tablelocated near an imaging table upon which a patient lays. The table isportable (e.g., on wheels) and connectable to the imaging table so thatthey move together. The table contains arm, which may be flexible ortelescoping, so as to permit positioning of the arm above and over thepatient. The transport sheath, or cables connected to the transportsheath, run along the arm to the overhead position. At the end of thearm is the procedure device pod. In some embodiments, two or more armsare provided with two or more procedure device pods or two or moresub-components of a single procedure device pod. The procedure devicepod is small (e.g., less than 1 foot cube, less than 10 cm cube, etc.)to allow easy movement and positioning above the patient. The proceduredevice pod contains a processor for controlling all computing aspects ofthe system. The device pod contains one or more connections ports forconnecting cables that lead to energy delivery devices. Cables areconnected to the ports. The cables are retractable and less than threefeet in length. Use of short cables reduces expense and prevents powerloss. When not in use, the cables hang in the air above the patient, outof contact with the patient's body. The ports are configured with adummy load when not in use (e.g., when an energy delivery device is notconnected to a particular port). The procedure device pod is withinreach of the treating physician so that computer controls can beadjusted and displayed information can be viewed, in real-time, during aprocedure.

X. Uses for Energy Delivery Systems

The systems of the present invention are not limited to particular uses.Indeed, the energy delivery systems of the present invention aredesigned for use in any setting wherein the emission of energy isapplicable. Such uses include any and all medical, veterinary, andresearch applications. In addition, the systems and devices of thepresent invention may be used in agricultural settings, manufacturingsettings, mechanical settings, or any other application where energy isto be delivered.

In some embodiments, the systems are configured for open surgery,percutaneous, intravascular, intracardiac, endoscopic, intraluminal,laparoscopic, or surgical delivery of energy. In some embodiments, theenergy delivery devices may be positioned within a patient's bodythrough a catheter, through a surgically developed opening, and/orthrough a body orifice (e.g., mouth, ear, nose, eyes, vagina, penis,anus) (e.g., a N.O.T.E.S. procedure). In some embodiments, the systemsare configured for delivery of energy to a target tissue or region. Insome embodiments, a positioning plate is provided so as to improvepercutaneous, intravascular, intracardiac, laparoscopic, and/or surgicaldelivery of energy with the energy delivery systems of the presentinvention. The present invention is not limited to a particular typeand/or kind of positioning plate. In some embodiments, the positioningplate is designed to secure one or more energy delivery devices at adesired body region for percutaneous, intravascular, intracardiac,laparoscopic, and/or surgical delivery of energy. In some embodiments,the composition of the positioning plate is such that it is able toprevent exposure of the body region to undesired heat from the energydelivery system. In some embodiments, the plate provides guides forassisted positioning of energy delivery devices. The present inventionis not limited by the nature of the target tissue or region. Usesinclude, but are not limited to, treatment of heart arrhythmia, tumorablation (benign and malignant), control of bleeding during surgery,after trauma, for any other control of bleeding, removal of soft tissue,tissue resection and harvest, treatment of varicose veins, intraluminaltissue ablation (e.g., to treat esophageal pathologies such as Barrett'sEsophagus and esophageal adenocarcinoma), treatment of bony tumors,normal bone, and benign bony conditions, intraocular uses, uses incosmetic surgery, treatment of pathologies of the central nervous systemincluding brain tumors and electrical disturbances, sterilizationprocedures (e.g., ablation of the fallopian tubes) and cauterization ofblood vessels or tissue for any purposes. In some embodiments, thesurgical application comprises ablation therapy (e.g., to achievecoagulative necrosis). In some embodiments, the surgical applicationcomprises tumor ablation to target, for example, metastatic tumors. Insome embodiments, the device is configured for movement and positioning,with minimal damage to the tissue or organism, at any desired location,including but not limited to, the lungs, brain, neck, chest, abdomen,and pelvis. In some embodiments, the systems are configured for guideddelivery, for example, by computerized tomography, ultrasound, magneticresonance imaging, fluoroscopy, and the like.

In certain embodiments, the present invention provides methods oftreating a tissue region, comprising providing a tissue region and asystem described herein (e.g., an energy delivery device, and at leastone of the following components: a processor, a power supply, atemperature monitor, an imager, a tuning system, a temperature reductionsystem, and/or a device placement system); positioning a portion of theenergy delivery device in the vicinity of the tissue region, anddelivering an amount of energy with the device to the tissue region. Insome embodiments, the tissue region is a tumor. In some embodiments, thedelivering of the energy results in, for example, the ablation of thetissue region and/or thrombosis of a blood vessel, and/orelectroporation of a tissue region. In some embodiments, the tissueregion is a tumor. In some embodiments, the tissue region comprises oneor more of the lung, heart, liver, genitalia, stomach, lung, largeintestine, small intestine, brain, neck, bone, kidney, muscle, tendon,blood vessel, prostate, bladder, and spinal cord.

In some embodiments, the present invention provides systems that accessto a difficult to reach region of the body (e.g. the periphery of thelungs). In some embodiments, the system navigates through a branchedbody structure (e.g. bronchial tree) to reach a target site. In someembodiments, systems, devices, and methods of the present inventionprovide delivery of energy (e.g. microwave energy, energy for tissueablation) to difficult to reach regions of a body, organ, or tissue(e.g. the periphery of the lungs). In some embodiments, the systemdelivers energy (e.g. microwave energy, energy for tissue ablation) to atarget site though a branched structure (e.g. bronchial tree). In someembodiments, the system delivers energy (e.g. microwave energy, energyfor tissue ablation) to the periphery of the lungs through the bronchi(e.g. primary bronchi, secondary bronchi, tertiary bronchi, bronchioles,etc.). In some embodiments, accessing the lungs through the bronchiprovides a precise and accurate approach while minimizing collateraldamage to the lungs. Accessing the lung (e.g. lung periphery) fromoutside the lung requires puncturing or cutting the lung, which can beavoided by bronchial access. Insertion through the lung has medicalcomplications that are avoided by the systems and methods of embodimentsof the present invention.

In some embodiments, a primary catheter (e.g. endoscope, bronchoscope,etc.), containing a channel catheter and steerable navigation catheteris advanced into the bronchial tree (e.g. via the trachea) until thedecreasing circumference of the bronchi will not allow furtheradvancement of the primary catheter. In some embodiments, a primarycatheter (e.g. endoscope, bronchoscope, etc.), containing a channelcatheter and steerable navigation catheter is advanced into thebronchial tree (e.g. via the trachea) up to the desired point fordeployment of the channel catheter. In some embodiments, the primarycatheter is advanced into the trachea, primary bronchi, and/or secondarybronchi, but not further. In some embodiments, a channel cathetercontaining a steerable navigation catheter is advanced through theprimary catheter, and beyond the distal tip of the primary catheter,into the bronchial tree (e.g. via the trachea, via the primary bronchi,via secondary bronchi, via tertiary bronchi, via bronchioles, etc.) upto the target location (e.g. treatment site, tumor, etc.). In someembodiments, a channel catheter containing a steerable navigationcatheter is advanced into the bronchial tree (e.g. via the trachea,primary bronchi, etc.) until the decreasing size of the bronchi will notallow further advancement (e.g. in the tertiary bronchi, in thebronchioles, at the treatment site). In some embodiments, the channelcatheter is advanced into the trachea, primary bronchi, secondarybronchi, tertiary bronchi, and/or bronchioles. In some embodiments, thesteerable navigation catheter is advanced into the trachea, primarybronchi, secondary bronchi, tertiary bronchi, and/or bronchioles to thetreatment site. In some embodiments, the steerable navigation catheteris withdrawn through the channel catheter, leaving the open channellumen extending from the point of insertion (e.g. into the subject, intothe trachea, into the bronchial tree, etc.), through the bronchial tree(e.g. through the trachea, primary bronchi, secondary bronchi, tertiarybronchi, bronchioles, etc.) to the target site (e.g. treatment site,tumor, peripheral lunch tumor). In some embodiments, an energy deliverydevice (e.g. microwave ablation device) is inserted through the openchannel lumen to access the target site. In some embodiments, thepresent invention provides systems, devices, and method to accessperipheral lung tumors through the bronchial tree with a microwaveablation device.

In some embodiments, the present invention provides systems, methods,and devices for placement of an energy delivery device at a difficult toaccess tissue region within a subject. In some embodiments, the presentinvention provides placement of an energy delivery device for tissueablation therapy (e.g. tumor ablation). In some embodiments, the presentinvention provides access to, and/or treatment of, tumors, growths,and/or nodules on the periphery of the lungs. In some embodiments, thepresent invention provides access to, and ablation of, peripheralpulmonary nodules. Peripheral pulmonary nodules are difficult to accessthrough the bronchial tree because of their location near the tertiarybronchi and bronchioles, beyond the reach of conventional devices andtechniques. In some embodiments, devices, systems, and methods of thepresent invention provide access to peripheral pulmonary nodules throughthe bronchial tree. Peripheral pulmonary nodules are generally less than25 mm in diameter (e.g. <25 mm, <20 mm, <10 mm, <5 mm, <2 mm, <1 mm,etc.). In some embodiments, peripheral pulmonary nodules are 0.1 mm-25mm in diameter (e.g. 0.1 mm . . . 0.2 mm . . . 0.5 mm . . . 1.0 mm . . .1.4 mm . . . 2.0 mm . . . 5.0 mm . . . 10 mm . . . 20 mm . . . 25 mm,and diameters therein). In some embodiments, the present inventionprovides access and treatment of tumors, growths, and nodules of anysize and any location within a subject (e.g. within the lungs of asubject). In some embodiments, the present invention provides curativetreatment and/or palliative treatment of tumors (e.g. nodules) in theperipheral lung.

XI. Device Placement Systems

In some embodiments, the present invention provides a primary catheter(e.g. endoscope, bronchoscope, etc.). In some embodiments, any suitableendoscope or bronchoscope known to those in the art finds use as aprimary catheter in the present invention. In some embodiments, aprimary catheter adopts characteristics of one or more endoscopes and/orbronchoscopes known in the art, as well as characteristics describedherein. One type of conventional flexible bronchoscope is described inU.S. Pat. No. 4,880,015, herein incorporated by reference in itsentirety. The bronchoscope measures 790 mm in length and has two mainparts, a working head and an insertion tube. The working head containsan eyepiece; an ocular lens with a diopter adjusting ring; attachmentsfor suction tubing, a suction valve, and light source; and an accessport or biopsy inlet, through which various devices and fluids can bepassed into the working channel and out the distal end of thebronchoscope. The working head is attached to the insertion tube, whichtypically measures 580 mm in length and 6.3 mm in diameter. Theinsertion tube contains fiberoptic bundles, which terminate in theobjective lens at the distal tip, light guides, and a working channel.Other endoscopes and bronchoscopes which may find use in embodiments ofthe present invention, or portions of which may find use with thepresent invention, are described in U.S. Pat. No. 7,473,219; U.S. Pat.No. 6,086,529; U.S. Pat. No. 4,586,491; U.S. Pat. No. 7,263,997; U.S.Pat. No. 7,233,820; and U.S. Pat. No. 6,174,307.

In some embodiments, the present invention provides a channel catheter(a.k.a. guide catheter, sheath, sheath catheter, etc.). In someembodiments, a guide catheter is configured to fit within the lumen of aprimary catheter and contains a channel lumen of sufficient diameter(e.g. 1 mm . . . 2 mm . . . 3 mm . . . 4 mm . . . 5 mm) to accommodate asteerable navigation catheter and/or one or more suitable tools (e.g.energy delivery device). In some embodiments, a channel catheter is ofsufficient length to extend from an insertion site (e.g. mouth, incisioninto body of subject, etc.) through the trachea and/or bronchial tree toa treatment site in the peripheral lung (e.g. 50 cm . . . 75 cm . . . 1m . . . 1.5 m . . . 2 m). In some embodiments, a channel catheter is ofsufficient length to extend beyond the reach of a primary catheter toreach a treatment site (e.g. peripheral lung tissue). In someembodiments, a channel catheter is highly flexible to access acircuitous route through a subject (e.g. through a branched structure,through the bronchial tree, etc.). In some embodiments, a channelcatheter is constructed of braided material to provide both strength andflexibility, as is understood in the art. In some embodiments, a channelcatheter comprises the outer conductor of a triaxial transmission line.In some embodiments, a channel catheter comprises a navigation and/orsteering mechanism. In some embodiments, a channel catheter is withoutan independent means of navigation, position recognition, ormaneuvering. In some embodiments, a channel catheter relies upon theprimary catheter or steerable navigation catheter for placement.

In some embodiments, the present invention provides a steerablenavigation catheter. In some embodiments, a steerable navigationcatheter is configured to fit within the lumen of a channel catheter. Insome embodiments, a steerable navigation catheter has a similar diameterto energy transmission lines described herein (e.g. 0.2 mm . . . 0.5 mm. . . 1.0 mm . . . 1.5 mm . . . 2.0 mm). In some embodiments, asteerable navigation catheter is of sufficient length to extend from aninsertion site (e.g. mouth, incision into body of subject, etc.) to atreatment site (e.g. through the trachea and/or bronchial tree to atreatment site in the peripheral lung (e.g. 50 cm . . . 75 cm . . . 1 m. . . 1.5 m . . . 2 m). In some embodiments, a channel catheter is ofsufficient length to extend beyond the reach of a primary catheter toreach a treatment site (e.g. peripheral lung tissue). In someembodiments, a steerable navigation catheter engages a channel cathetersuch that movement of the steerable navigation catheter results insynchronous movement of the channel catheter. In some embodiments, as asteerable navigation catheter is inserted along a path in a subject, thechannel catheter surrounding the steerable navigation catheter moveswith it. In some embodiments, a channel catheter is placed within asubject by a steerable navigation catheter. In some embodiments, asteerable navigation catheter can be disengaged from a channel catheter.In some embodiments, disengagement of a steerable navigation catheterand channel catheter allows movement of the steerable navigationcatheter further along a pathway without movement of the channelcatheter. In some embodiments, disengagement of a steerable navigationcatheter and channel catheter allows retraction of the steerablenavigation catheter through the channel catheter without movement of thechannel catheter.

In some embodiments, all inserted components of a system or device areconfigured for movement along a narrow and circuitous path through asubject (e.g. through a branched structure, through the bronchial tree,etc.). In some embodiment, components comprise a flexible materialconfigured for tight turning radiuses. In some embodiment, necessarilyrigid components are reduced in size (e.g. short length) to allow fortight turning radiuses.

EXPERIMENTAL Example I

This example demonstrates the avoidance of undesired tissue heatingthrough use of an energy delivery device of the present inventioncirculating coolant through coolant channels. The ablation needle shaftfor all experiments was 20.5 cm. There was minimal cooling of the handleassembly indicating that handle-cooling effects were well-isolated.Temperature probes 1, 2 and 3 were located at 4, 8 and 12 cm proximal tothe tip of the stainless needle (see FIG. 9). Temperature measurementswere taken for 35% power measurement following insertion into a pigliver and 45% power measurement following insertion into a pig liver.For the 35% power measurement, Probe 4 was on the handle itself. For the45% power measurements, Probe 4 was located at the needle-skininterface, approximately 16 cm back from the stainless needle tip.

As shown in FIG. 10, treatment at 35% power for 10 minutes withanonymously high (6.5%) reflected power demonstrated maintenance of thedevice at a non-tissue damaging temperature at Probes 1, 2, 3 and thehandle.

As shown in FIG. 11, treatment at 45% power for 10 minutes withanonymously high (6.5%) reflected power demonstrated maintenance of thedevice at a non-tissue damaging temperature at Probes 1, 2, 3 and 4.Observation of the skin and fat layers after 10 minutes ablation at 45%power for 10 minutes with anonymously high (6.5%) reflected powerdemonstrating no visible burns or thermal damage.

Example II

This example demonstrates generator calibration. Generator calibrationwas done by Cober-Muegge at the factory and was set to be most accuratefor powers greater than 150 W. The magnetron behaved much like a diode:increasing cathode voltage did not increase vacuum current (proportionalto output power) until a critical threshold was reached, at which pointvacuum current increased rapidly with voltage. Control of the magnetronsource relied on accurate control of the cathode voltage near thatcritical point. As such, the generator was not specified for powers from0-10% and correlation between the output power and theoretical powerpercentage input was poor below 15%.

To test the generator calibration, the power control dial was changedfrom 0.25% in 1% increments (corresponding to theoretical output powersof 0-75 W in 3 W increments) and the generator's output power displaywas recorded and power output measured. The measured power output wasadjusted for the measured losses of the coaxial cable, coupler and loadat room temperature. The output display was also adjusted for offseterror (i.e., the generator read 2.0% when the dial was set to 0.0%).

The error between the dial and generator output power display was largefor low-power dial settings. These two values quickly converged to apercent error of less than 5% for dial settings above 15%. Similarly,the measured output power was significantly different from thetheoretical output power for dial settings below 15% but more accuratefor dial settings above 15%.

Example III

This example describes the setup and testing of an antenna duringmanufacturing. This provides a method for setup and tested in amanufacturing environment. The method employs a liquid,tissue-equivalent phantom rather than tissue.

From the numerical and experimental measurements already made on theantenna, it was known that changes in L2 of ˜1 mm will increase thereflected power from <−30 dB to ˜−20-25 dB. This increase was likelymade less significant by the changes in tissue properties that occurredduring ablation and so we would consider at relative tolerance of 0.5 mmon the length L2 is reasonable. Likewise, a tolerance of 0.5 mm on thelength L1 is used, even though the total reflection coefficient dependsless on L1 than L2.

Testing of the antenna tuning for quality control purposes can beachieved using a liquid solution designed to mimic the dielectricproperties of liver, lung or kidney (see, e.g., Guy A W (1971) IEEETrans. Microw. Theory Tech. 19:189-217; herein incorporated by referencein its entirety). The antenna is immersed in the phantom and thereflection coefficient recorded using a 1-port measurement device orfull vector network analyzer (VNA). Verification of a reflectioncoefficient below −30 dB is selected to ensure proper tuning.

Example IV

This example compared the efficiency, heating ability, andmanufacturability of the triaxial and center-fed dipole antennas.Modification of the original triaxial design was required to create amore rigid, sharp tip that could be easily inserted. Computer modelingwas initially used to determine what changes in antenna length might berequired with the addition of an alumina sheath and faceted metallictip. After modeling confirmed that the antenna would need to belengthened and the metallic tip would not degrade performance, antennaswere constructed for testing in ex vivo liver tissue. This testingshowed that the modified design retained its high efficiency whileproviding enough mechanical strength for percutaneous placement.Computer modeling of the center-fed dipole design yielded marginalresults and subsequent device fabrication proved difficult to reproduce.Accordingly, the insertable triaxial device was chosen as a lead antennadesign.

Computer modeling revealed that both thermally-resistive coatings andserious thermal breaks can reduce the amount of heat that is allowed toflow from the distal antenna tip to proximal sections of the antenna.However, an effective water cooling solution was able to increase thepower throughput of a 0.020″ coaxial cable from ˜8 W to over 150 W.Water cooling also eliminated any shaft heating extending proximallyfrom the antenna tip when using 150 W input power (FIG. 21). However,implementation required the use of expensive 0.020″ coaxial cable toprovide sufficient water flow rates (˜30 ml/min). In addition, 0.020″cable is 2-3× more lossy than the 0.047″ cable used previously, whichdecreased power throughput by as much as 15 W and required cooling ofthat additional power loss. The final antenna design incorporated a PEEKsheath around the entire assembly to reduce sticking that can occurbetween a metallic antenna and surrounding tissue while also providingthe thermal buffer shown to reduce thermally conductive heating.

A study was performed percutaneously using either the cooled, 17-gaugeprototype antenna or 17-gauge cooled RF electrode fromValleylab/Covidien to create ablations in a normal, in vivo porcine lungmodel. Ablations were performed for 10 min using the clinical standardof 200 W with impedance control for RF and 135 W for the microwavegroup. Ablations created in the microwave group were significantlylarger than in the RF group with a mean ablation diameter (mean±standarddeviation) of 3.32±0.19 cm and 2.7±0.27 cm, respectively (P<0.0001, FIG.9). Ablation circularity was also significantly higher in the microwavegroup than in the RF group (0.90±0.06 vs. 0.82±0.09, P<0.05). No majorcomplications were observed throughout the entire study. Minorpneumothoraces were observed in one animal during two ablations, bothfrom the RF group. Both remained stable without intervention. From thisstudy, it was concluded that microwaves are more effective and typicallyfaster than RF current for heating lung tissue.

Example V

This example investigated cooling in a simulated heating environment. Aheater coil was passed through a 17-gauge stainless needle nearlyidentical to the third conductor of the triaxial antenna. Fourthermocouples were placed along the outside of the needle and the entiresystem thermally isolated with closed-cell foam. This setup wasconsidered worst-case, since blood flow and the high thermalconductivity of biological tissues will tend to provide some antennacooling. The coil was heated with 0-50 W and temperatures recorded withNC—CO₂ operating at 0-10 stp L/min flow rates. Test results showed thata moderate flow of CO2 was sufficient to cool the entire 50 W inputpower so that the heated tube remained at ambient temperature (FIG. 24).

Temperatures recorded on the outer surface of the needle without coolingpresent exceeded 100° C., but cooling with 10-20 stp L/min of NC—CO₂reduced the surface temperature to below 30° C. (FIG. 24). These testsshowed that moderate amounts of NC—CO₂ (˜10 stp L/min) can effectivelycool as much as 50 W from the inside of an ablation antenna.

Example VI

This experiment measured the effects of thermal conduction proximallyfrom the heated antenna tip. A modified antenna—with the ceramicradiating segment replaced with a thermally-conductive copper tube—wasplaced into an electric heater with thermal paste to ensure a goodthermal contact between the heater and antenna (FIG. 25). Thermocoupleswere placed along the outer surface of the antenna at several points tomeasure temperature versus NC—CO₂ flow rate.

Before cooling, temperatures along the outer conductor exceeded 80° C. 1cm proximal to the heater. When cooling was initiated even at a modestrate of 13 stp L/min, temperatures dropped to the input temperature ofthe NC—CO₂ gas: ˜0° C. (FIG. 25). Increasing the flow rate decreasedtemperatures even further. Gas was precooled slightly in aheat-exchanger to test the possibility of a “stick” function on theneedle shaft, similar to that employed by cryoablation probes. Thisprecooling led to the lower-than-required temperature of 31° C. fornear-critical operation and additional implementation was beyond thescope of this investigation.

Follow-up tests using the same setup and heater was also performed toevaluate the lower-limit of cooling power required. In this study, aninitial flow of 10 stp L/min was shown to decrease temperatures to ˜0°C. That flow was then removed and pulses of CO2 at 1 stp L/min wereinjected for approximately 10 s when the shaft temperature rose morethan 30° C. Despite rapid rises in temperature without cooling, onlysmall pulses of CO₂ were required to eliminate temperature rise and keepthe system at ambient temperature (FIG. 26). These results suggest, forexample, that small amounts of CO₂ may be able to be used to keep theantenna below ISO 60601-1 standards during the procedure. A temperaturefeedback/monitoring system could be employed to minimize the use of CO₂during the procedure. Near-critical CO₂ is a feasible and effectivealternative to liquid cooling inside microwave ablation antennas. Theincreased heat capacity of NC—CO₂ ensures that only small volumes offluid are required to cool the ablation antenna to safe levels. It wasshown that modest flow rates ˜10 stp L/min were sufficient to coolantennas generating as much as 50 W.

Example VII

This example assessed the feasibility of using small, periodicinjections of iodinated contrast material over the course of theablation with a new reconstruction technique to improve ablation zonevisualization while reducing contrast material dose. The lack of aubiquitous and effective intra-procedural imaging technique is acritical limitation to the field of thermal tumor ablation. Ultrasoundimaging can be obscured by bubbles formed while heating, andcontrast-enhanced CT is typically limited to one scan with a largeinjection of contrast material.

Female domestic swine were prepared and anesthetized. RF ablation wasperformed for 20 min using three internally-cooled, switched electrodes.During ablation, 15 ml iodinated contrast material (300 mg/ml) wasdelivered every 2 min and an abdominal CT collected at thepre-determined liver enhancement time following each injection (90 s).CT images were created using both conventional online reconstruction andoffline reconstruction with HighlY-constrained backPRojection (HYPR).Conventional and HYPR-reconstructed images were compared for imagingcontrast between the ablation zone and background liver and signal tonoise ratios.

Ablation zone growth was able to be visualized with 2 min temporalresolution. The ablation zone became readily apparent in 2-6 min with acumulative contrast dose of 15-45 ml. Image quality improved withcumulative contrast dose. SNR in HYPR-reconstructed images was 3-4×better than standard reconstructions and HYPR improved signal contrastbetween the ablation zone and background liver by up to 6× (FIGS. 27 and28).

All publications and patents mentioned in the above specification areherein incorporated by reference. Various modifications and variationsof the described method and system of the invention will be apparent tothose skilled in the art without departing from the scope and spirit ofthe invention. Although the invention has been described in connectionwith specific embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments.Indeed, various modifications of the described modes for carrying outthe invention that are obvious to those skilled in the relevant fieldsare intended to be within the scope of the following claims.

We claim:
 1. A method of treating a peripheral lung nodule comprisingablating said nodule by application of microwave energy.
 2. The methodof claim 1, wherein said microwave energy is delivered along a microwavedelivery device.
 3. The method of claim 2, wherein said microwavedelivery device is inserted through the bronchial tree of a subject. 4.A system comprising: a) a primary catheter, wherein said primarycatheter comprises a primary lumen; b) a channel catheter, wherein saidchannel catheter is configured to fit within said primary lumen, andwherein said channel catheter comprises a channel lumen; c) a steerablenavigation catheter, wherein said steerable navigation catheter isconfigured to fit within said channel lumen, and wherein said steerablenavigation catheter comprises a steerable tip and position sensingelement; and d) an energy delivery device, wherein said energy deliverydevice is configured to fit within said channel lumen.
 5. The system ofclaim 4, wherein said primary catheter comprises a bronchoscope.
 6. Thesystem of claim 4, wherein said energy delivery device comprises amicrowave ablation device.
 7. The system of claim 4, further comprisinga handle for manipulation of one or more of said primary catheter, saidchannel catheter, said steerable navigation catheter, and said energydelivery device.
 8. The system of claim 4, further comprising aprocessor operation of the components of said system.
 9. The system ofclaim 4, wherein said energy delivery device is capable of deliveringmicrowave energy through said channel catheter.
 10. A method of placingan energy delivery device at a difficult to reach treatment sitecomprising: a) providing the system of claim 1, wherein said steerablenavigation catheter is within the channel lumen, and said channelcatheter is within said primary lumen; b) inserting said primarycatheter into an opening in a subject and directing said primarycatheter towards said treatment site until further advance isconstrained by the diameter of said primary catheter; c) advancing saidchannel catheter beyond the distal end of said primary catheter andextending said channel catheter to said treatment site; d) securing thedistal end of said channel catheter at said treatment site; e)withdrawing said steerable navigation catheter through said channellumen and out the proximal end of said channel catheter; f) insertingsaid energy delivery device through said channel lumen until the distalend of said energy delivery device reaches said treatment site.
 11. Themethod of claim 10, wherein said difficult to reach treatment sitecomprises the periphery of the lung.
 12. The method of claim 11, whereinsaid difficult to reach treatment site comprises a peripheral lungnodule.
 13. The method of claim 12, wherein said lung nodule is accessedthrough the bronchial tree.